import java.util.*;
import java.util.zip.*;
import java.util.List;
import java.util.regex.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.util.concurrent.locks.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.table.*;
import java.io.*;
import java.net.*;
import java.lang.reflect.*;
import java.lang.ref.*;
import java.lang.management.*;
import java.security.*;
import java.security.spec.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.imageio.*;
import java.math.*;
class main {

static void test_compress30BitUint() {
  for (int _repeat_0 = 0; _repeat_0 < 100000; _repeat_0++)  {
    int i = random(0x40000000);
    byte[] b = compress30BitUint(i);
    assertEquals(i, readCompressed30BitUint(byteArrayToIF0_Byte(b)));
  }
}
static Random random_random = new Random();

static int random(int n) {
  return random(random_random, n);
}

static int random(int n, Random r) { return random(r, n); }

static int random(Random r, int n) {
  return n <= 0 ? 0 : r.nextInt(n);
}

static double random(double max) {
  return random()*max;
}

static double random() {
  return random_random.nextInt(100001)/100000.0;
}

static double random(double min, double max) {
  return min+random()*(max-min);
}

// min <= value < max
static int random(int min, int max) {
  return min+random(max-min);
}

static int random(int min, int max, Random r) {
  return random(r, min, max);
}

static int random(Random r, int min, int max) {
  return min+random(r, max-min);
}

static <A> A random(List<A> l) {
  return oneOf(l);
}

static <A> A random(Collection<A> c) {
  if (c instanceof List) return random((List<A>) c);
  int i = random(l(c));
  return collectionGet(c, i);
}


static byte[] compress30BitUint(int i) {
  if (i < 0 || i >= 0x40000000) throw fail("Not a 30 bit uint: " + i);
  if (i < 0x40)
    return new byte[] { (byte) i };
  if (i < 0x4000)
    return new byte[] {
      (byte) ((i >> 8) | 0x40),
      (byte) i
    };
  if (i < 0x400000)
    return new byte[] {
      (byte) ((i >> 16) | 0x80),
      (byte) (i >> 8),
      (byte) i
    };
  return new byte[] {
    (byte) ((i >> 24) | 0xC0),
    (byte) (i >> 16),
    (byte) (i >> 8),
    (byte) i
  };
}
static <A> A assertEquals(Object x, A y) {
  return assertEquals(null, x, y);
}

static <A> A assertEquals(String msg, Object x, A y) {
  if (assertVerbose()) return assertEqualsVerbose(msg, x, y);
  if (!(x == null ? y == null : x.equals(y)))
    throw fail((msg != null ? msg + ": " : "") + y + " != " + x);
  return y;
}
static int readCompressed30BitUint(IF0_Byte readByte) {
  int i = ubyteToInt(readByte.get());
  if (i < 0x40) return i;
  if (i < 0x80)
    return ((i & 0x3F) << 8) | ubyteToInt(readByte.get());
  int j = ubyteToInt(readByte.get());
  if (i < 0xC0)
    return ((i & 0x3F) << 16)
      | (j << 8) | ubyteToInt(readByte.get());
  int k = ubyteToInt(readByte.get());
    return ((i & 0x3F) << 24)
      | (j << 16) | (k << 8) | ubyteToInt(readByte.get());
}
static IF0_Byte byteArrayToIF0_Byte(byte[] array) {
  return new IF0_Byte() {
    int i;
    
    public byte get() { return array[i++]; }
  };
}


static <A> A oneOf(List<A> l) {
  return empty(l) ? null : l.get(new Random().nextInt(l.size()));
}

static char oneOf(String s) {
  return empty(s) ? '?' : s.charAt(random(l(s)));
}

static String oneOf(String... l) {
  return oneOf(asList(l));
}
static int l(Object[] a) { return a == null ? 0 : a.length; }
static int l(boolean[] a) { return a == null ? 0 : a.length; }
static int l(byte[] a) { return a == null ? 0 : a.length; }
static int l(short[] a) { return a == null ? 0 : a.length; }
static int l(long[] a) { return a == null ? 0 : a.length; }
static int l(int[] a) { return a == null ? 0 : a.length; }
static int l(float[] a) { return a == null ? 0 : a.length; }
static int l(double[] a) { return a == null ? 0 : a.length; }
static int l(char[] a) { return a == null ? 0 : a.length; }
static int l(Collection c) { return c == null ? 0 : c.size(); }

static int l(Iterator i) { return iteratorCount_int_close(i); } // consumes the iterator && closes it if possible

static int l(Map m) { return m == null ? 0 : m.size(); }
static int l(CharSequence s) { return s == null ? 0 : s.length(); }
static long l(File f) { return f == null ? 0 : f.length(); }



static int l(Object o) {
  return o == null ? 0
    : o instanceof String ? l((String) o)
    : o instanceof Map ? l((Map) o)
    : o instanceof Collection ? l((Collection) o)
    : o instanceof Object[] ? l((Object[]) o)
    : o instanceof boolean[] ? l((boolean[]) o)
    : o instanceof byte[] ? l((byte[]) o)
    : o instanceof char[] ? l((char[]) o)
    : o instanceof short[] ? l((short[]) o)
    : o instanceof int[] ? l((int[]) o)
    : o instanceof float[] ? l((float[]) o)
    : o instanceof double[] ? l((double[]) o)
    : o instanceof long[] ? l((long[]) o)
    : (Integer) call(o, "size");
}














static <A> A collectionGet(Collection<A> c, int idx) {
  if (c == null || idx < 0 || idx >= l(c)) return null;
  if (c instanceof List) return listGet((List<A>) c, idx);
  Iterator<A> it = c.iterator();
  for (int i = 0; i < idx; i++) if (it.hasNext()) it.next(); else return null;
  return it.hasNext() ? it.next() : null;
}
static RuntimeException fail() { throw new RuntimeException("fail"); }
static RuntimeException fail(Throwable e) { throw asRuntimeException(e); }
static RuntimeException fail(Object msg) { throw new RuntimeException(String.valueOf(msg)); }
static RuntimeException fail(String msg) { throw new RuntimeException(msg == null ? "" : msg); }
static RuntimeException fail(String msg, Throwable innerException) { throw new RuntimeException(msg, innerException); }

static ThreadLocal<Boolean> assertVerbose_value = new ThreadLocal();

static void assertVerbose(boolean b) {
  assertVerbose_value.set(b);
}

static boolean assertVerbose() { return isTrue(assertVerbose_value.get()); }
static <A> A assertEqualsVerbose(Object x, A y) {
  assertEqualsVerbose((String) null, x, y);
  return y;
}

// x = expected, y = actual
static <A> A assertEqualsVerbose(String msg, Object x, A y) {
  if (!eq(x, y)) {
    

    throw fail((msg != null ? msg + ": " : "") + "expected: "+ x + ", got: " + y);
  } else
    print("OK" + (empty(msg) ? "" : " " + msg) + ": " + /*sfu*/(x));
  return y;
}


static int ubyteToInt(byte b) {
  return b & 0x0FF;
}
// get purpose 1: access a list/array/map (safer version of x.get(y))

static <A> A get(List<A> l, int idx) {
  return l != null && idx >= 0 && idx < l(l) ? l.get(idx) : null;
}

// seems to conflict with other signatures
/*static <A, B> B get(Map<A, B> map, A key) {
  ret map != null ? map.get(key) : null;
}*/

static <A> A get(A[] l, int idx) {
  return idx >= 0 && idx < l(l) ? l[idx] : null;
}

// default to false
static boolean get(boolean[] l, int idx) {
  return idx >= 0 && idx < l(l) ? l[idx] : false;
}

// get purpose 2: access a field by reflection or a map

static Object get(Object o, String field) {
  try {
    if (o == null) return null;
    if (o instanceof Class) return get((Class) o, field);
    
    if (o instanceof Map)
      return ((Map) o).get(field);
      
    Field f = getOpt_findField(o.getClass(), field);
    if (f != null) {
      makeAccessible(f);
      return f.get(o);
    }
      
    
  } catch (Exception e) {
    throw asRuntimeException(e);
  }
  throw new RuntimeException("Field '" + field + "' not found in " + o.getClass().getName());
}

static Object get_raw(String field, Object o) {
  return get_raw(o, field);
}

static Object get_raw(Object o, String field) { try {
  if (o == null) return null;
  Field f = get_findField(o.getClass(), field);
  makeAccessible(f);
  return f.get(o);
} catch (Exception __e) { throw rethrow(__e); } }

static Object get(Class c, String field) {
  try {
    Field f = get_findStaticField(c, field);
    makeAccessible(f);
    return f.get(null);
  } catch (Exception e) {
    throw new RuntimeException(e);
  }
}

static Field get_findStaticField(Class<?> c, String field) {
  Class _c = c;
  do {
    for (Field f : _c.getDeclaredFields())
      if (f.getName().equals(field) && (f.getModifiers() & java.lang.reflect.Modifier.STATIC) != 0)
        return f;
    _c = _c.getSuperclass();
  } while (_c != null);
  throw new RuntimeException("Static field '" + field + "' not found in " + c.getName());
}

static Field get_findField(Class<?> c, String field) {
  Class _c = c;
  do {
    for (Field f : _c.getDeclaredFields())
      if (f.getName().equals(field))
        return f;
    _c = _c.getSuperclass();
  } while (_c != null);
  throw new RuntimeException("Field '" + field + "' not found in " + c.getName());
}

static Object get(String field, Object o) {
  return get(o, field);
}


static boolean empty(Collection c) { return c == null || c.isEmpty(); }
static boolean empty(Iterable c) { return c == null || !c.iterator().hasNext(); }
static boolean empty(CharSequence s) { return s == null || s.length() == 0; }
static boolean empty(Map map) { return map == null || map.isEmpty(); }
static boolean empty(Object[] o) { return o == null || o.length == 0; }
static boolean empty(Object o) {
  if (o instanceof Collection) return empty((Collection) o);
  if (o instanceof String) return empty((String) o);
  if (o instanceof Map) return empty((Map) o);
  if (o instanceof Object[]) return empty((Object[]) o);
  if (o instanceof byte[]) return empty((byte[]) o);
  if (o == null) return true;
  throw fail("unknown type for 'empty': " + getType(o));
}

static boolean empty(Iterator i) { return i == null || !i.hasNext(); }

static boolean empty(double[] a) { return a == null || a.length == 0; }
static boolean empty(float[] a) { return a == null || a.length == 0; }
static boolean empty(int[] a) { return a == null || a.length == 0; }
static boolean empty(long[] a) { return a == null || a.length == 0; }
static boolean empty(byte[] a) { return a == null || a.length == 0; }
static boolean empty(short[] a) { return a == null || a.length == 0; }





static boolean empty(File f) { return getFileSize(f) == 0; }






// unclear semantics as to whether return null on null

static <A> ArrayList<A> asList(A[] a) {
  return a == null ? new ArrayList<A>() : new ArrayList<A>(Arrays.asList(a));
}

static ArrayList<Integer> asList(int[] a) {
  if (a == null) return null;
  ArrayList<Integer> l = emptyList(a.length);
  for (int i : a) l.add(i);
  return l;
}

static ArrayList<Float> asList(float[] a) {
  if (a == null) return null;
  ArrayList<Float> l = emptyList(a.length);
  for (float i : a) l.add(i);
  return l;
}

static ArrayList<Double> asList(double[] a) {
  if (a == null) return null;
  ArrayList<Double> l = emptyList(a.length);
  for (double i : a) l.add(i);
  return l;
}

static <A> ArrayList<A> asList(Iterable<A> s) {
  if (s instanceof ArrayList) return (ArrayList) s;
  ArrayList l = new ArrayList();
  if (s != null)
    for (A a : s)
      l.add(a);
  return l;
}



static <A> ArrayList<A> asList(Enumeration<A> e) {
  ArrayList l = new ArrayList();
  if (e != null)
    while (e.hasMoreElements())
      l.add(e.nextElement());
  return l;
}


static <A> int iteratorCount_int_close(Iterator<A> i) { try {
  int n = 0;
  if (i != null) while (i.hasNext()) { i.next(); ++n; }
  if (i instanceof AutoCloseable) ((AutoCloseable) i).close();
  return n;
} catch (Exception __e) { throw rethrow(__e); } }
static Object call(Object o) {
  return callF(o);
}

// varargs assignment fixer for a single string array argument
static Object call(Object o, String method, String[] arg) {
  return call(o, method, new Object[] {arg});
}

static Object call(Object o, String method, Object... args) {
  //ret call_cached(o, method, args);
  return call_withVarargs(o, method, args);
}
static <A> A listGet(List<A> l, int idx) {
  return l != null && idx >= 0 && idx < l(l) ? l.get(idx) : null;
}
static RuntimeException asRuntimeException(Throwable t) {
  
  if (t instanceof Error)
    _handleError((Error) t);
  
  return t instanceof RuntimeException ? (RuntimeException) t : new RuntimeException(t);
}
static boolean isTrue(Object o) {
  if (o instanceof Boolean)
    return ((Boolean) o).booleanValue();
  if (o == null) return false;
  if (o instanceof ThreadLocal) // TODO: remove this
    return isTrue(((ThreadLocal) o).get());
  throw fail(getClassName(o));
}
static boolean eq(Object a, Object b) {
  return a == b || a != null && b != null && a.equals(b);
}


static volatile StringBuffer local_log = new StringBuffer(); // not redirected




static volatile Appendable print_log = local_log; // might be redirected, e.g. to main bot

// in bytes - will cut to half that
static volatile int print_log_max = 1024*1024;
static volatile int local_log_max = 100*1024;

static boolean print_silent = false; // total mute if set

static Object print_byThread_lock = new Object();
static volatile ThreadLocal<Object> print_byThread; // special handling by thread - prefers F1<S, Bool>
static volatile Object print_allThreads;
static volatile Object print_preprocess;

static void print() {
  print("");
}

static <A> A print(String s, A o) {
  print((endsWithLetterOrDigit(s) ? s + ": " : s) + o);
  return o;
}

// slightly overblown signature to return original object...
static <A> A print(A o) {
  ping_okInCleanUp();
  if (print_silent) return o;
  String s = String.valueOf(o) + "\n";
  print_noNewLine(s);
  return o;
}

static void print_noNewLine(String s) {
  
  Object f = getThreadLocal(print_byThread_dontCreate());
  if (f == null) f = print_allThreads;
  if (f != null)
    // We do need the general callF machinery here as print_byThread is sometimes shared between modules
    if (isFalse(
      
        f instanceof F1 ? ((F1) f).get(s) :
      
      callF(f, s))) return;
  

  print_raw(s);
}

static void print_raw(String s) {
  
  if (print_preprocess != null) s = (String) callF(print_preprocess, s);
  s = fixNewLines(s);
  
  Appendable loc = local_log;
  Appendable buf = print_log;
  int loc_max = print_log_max;
  if (buf != loc && buf != null) {
    print_append(buf, s, print_log_max);
    loc_max = local_log_max;
  }
  if (loc != null) 
    print_append(loc, s, loc_max);
  
  
    System.out.print(s);
  
}

static void print_autoRotate() {
  
}
static Field getOpt_findField(Class<?> c, String field) {
  Class _c = c;
  do {
    for (Field f : _c.getDeclaredFields())
      if (f.getName().equals(field))
        return f;
    _c = _c.getSuperclass();
  } while (_c != null);
  return null;
}
static Field makeAccessible(Field f) {
  try {
    f.setAccessible(true);
  } catch (Throwable e) {
    // Note: The error reporting only works with Java VM option --illegal-access=deny
    
    vmBus_send("makeAccessible_error",e, f);
    
  }
  return f;
}

static Method makeAccessible(Method m) {
  try {
    m.setAccessible(true);
  } catch (Throwable e) {
    
    vmBus_send("makeAccessible_error",e, m);
    
  }
  return m;
}

static Constructor makeAccessible(Constructor c) {
  try {
    c.setAccessible(true);
  } catch (Throwable e) {
    
    vmBus_send("makeAccessible_error",e, c);
    
  }
  return c;
}
static RuntimeException rethrow(Throwable t) {
  
  if (t instanceof Error)
    _handleError((Error) t);
  
  throw t instanceof RuntimeException ? (RuntimeException) t : new RuntimeException(t);
}

static RuntimeException rethrow(String msg, Throwable t) {
  throw new RuntimeException(msg, t);
}


static AutoCloseable tempInterceptPrintIfNotIntercepted(F1<String, Boolean> f) {
  return print_byThread().get() == null ? tempInterceptPrint(f) : null;
}
static String getType(Object o) {
  return getClassName(o);
}
static long getFileSize(String path) {
  return path == null ? 0 : new File(path).length();
}

static long getFileSize(File f) {
  return f == null ? 0 : f.length();
}
static ArrayList emptyList() {
  return new ArrayList();
  //ret Collections.emptyList();
}

static ArrayList emptyList(int capacity) {
  return new ArrayList(max(0, capacity));
}

// Try to match capacity
static ArrayList emptyList(Iterable l) {
  return l instanceof Collection ? emptyList(((Collection) l).size()) : emptyList();
}

static ArrayList emptyList(Object[] l) {
  return emptyList(l(l));
}

// get correct type at once
static <A> ArrayList<A> emptyList(Class<A> c) {
  return new ArrayList();
}
static Map<Class, ArrayList<Method>> callF_cache = newDangerousWeakHashMap();




  static <A, B> B callF(F1<A, B> f, A a) {
    return f == null ? null : f.get(a);
  }











  static <A> void callF(VF1<A> f, A a) {
    if (f != null) f.get(a);
  }


static Object callF(Object f, Object... args) { try {
  if (f instanceof String)
    return callMCWithVarArgs((String) f, args); // possible SLOWDOWN over callMC
  if (f instanceof Runnable) {
    ((Runnable) f).run();
    return null;
  }
  if (f == null) return null;
  
  Class c = f.getClass();
  ArrayList<Method> methods;
  synchronized(callF_cache) {
    methods = callF_cache.get(c);
    if (methods == null)
      methods = callF_makeCache(c);
  }
  
  int n = l(methods);
  if (n == 0) {
    
    throw fail("No get method in " + getClassName(c));
  }
  if (n == 1) return invokeMethod(methods.get(0), f, args);
  for (int i = 0; i < n; i++) {
    Method m = methods.get(i);
    if (call_checkArgs(m, args, false))
      return invokeMethod(m, f, args);
  }
  throw fail("No matching get method in " + getClassName(c));
} catch (Exception __e) { throw rethrow(__e); } }

// used internally
static ArrayList<Method> callF_makeCache(Class c) {
  ArrayList<Method> l = new ArrayList();
  Class _c = c;
  do {
    for (Method m : _c.getDeclaredMethods())
      if (m.getName().equals("get")) {
        makeAccessible(m);
        l.add(m);
      }
    if (!l.isEmpty()) break;
    _c = _c.getSuperclass();
  } while (_c != null);
  callF_cache.put(c, l);
  return l;
}
static Object call_withVarargs(Object o, String method, Object... args) { try {
  if (o == null) return null;
  
  if (o instanceof Class) {
    Class c = (Class) o;
    _MethodCache cache = callOpt_getCache(c);
    
    Method me = cache.findStaticMethod(method, args);
    if (me != null)
      return invokeMethod(me, null, args);
      
    // try varargs
    List<Method> methods = cache.cache.get(method);
    if (methods != null) methodSearch: for (Method m : methods) {
      { if (!(m.isVarArgs())) continue; }
      { if (!(isStaticMethod(m))) continue; }
      Object[] newArgs = massageArgsForVarArgsCall(m, args);
      if (newArgs != null)
        return invokeMethod(m, null, newArgs);
    }
    
    throw fail("Method " + c.getName() + "." + method + "(" + joinWithComma(classNames(args)) + ") not found");
  } else {
    Class c = o.getClass();
    _MethodCache cache = callOpt_getCache(c);

    Method me = cache.findMethod(method, args);
    if (me != null)
      return invokeMethod(me, o, args);
      
    // try varargs
    List<Method> methods = cache.cache.get(method);
    if (methods != null) methodSearch: for (Method m : methods) {
      { if (!(m.isVarArgs())) continue; }
      Object[] newArgs = massageArgsForVarArgsCall(m, args);
      if (newArgs != null)
        return invokeMethod(m, o, newArgs);
    }
    
    throw fail("Method " + c.getName() + "." + method + "(" + joinWithComma(classNames(args)) + ") not found");
  }
} catch (Exception __e) { throw rethrow(__e); } }
static void _handleError(Error e) {
  call(javax(), "_handleError", e);
}
static String getClassName(Object o) {
  return o == null ? "null" : o instanceof Class ? ((Class) o).getName() : o.getClass().getName();
}
static String str(Object o) {
  return o == null ? "null" : o.toString();
}

static String str(char[] c) {
  return new String(c);
}
static boolean endsWithLetterOrDigit(String s) {
  return s != null && s.length() > 0 && Character.isLetterOrDigit(s.charAt(s.length()-1));
}
static void ping_okInCleanUp() {

  if (ping_pauseAll || ping_anyActions)
    ping_impl(true);

}
// this syntax should be removed...
static Object getThreadLocal(Object o, String name) {
  ThreadLocal t =  (ThreadLocal) (getOpt(o, name));
  return t != null ? t.get() : null;
}

static <A> A getThreadLocal(ThreadLocal<A> tl) {
  return tl == null ? null : tl.get();
}

static <A> A getThreadLocal(ThreadLocal<A> tl, A defaultValue) {
  return or(getThreadLocal(tl), defaultValue);
}
static ThreadLocal<Object> print_byThread_dontCreate() {
  return print_byThread;
}
static boolean isFalse(Object o) {
  return eq(false, o);
}
static String fixNewLines(String s) {
  int i = indexOf(s, '\r');
  if (i < 0) return s;
  int l = s.length();
  StringBuilder out = new StringBuilder(l);
  out.append(s, 0, i);
  for (; i < l; i++) {
    char c = s.charAt(i);
    if (c != '\r')
      out.append(c);
    else {
      out.append('\n');
      if (i+1 < l && s.charAt(i+1) == '\n') ++i;
    }
  }
  return out.toString();
}
static void print_append(Appendable buf, String s, int max) { try {
  synchronized(buf) {
    buf.append(s);
    if (buf instanceof StringBuffer)
      rotateStringBuffer(((StringBuffer) buf), max);
    else if (buf instanceof StringBuilder)
      rotateStringBuilder(((StringBuilder) buf), max);
  }
} catch (Exception __e) { throw rethrow(__e); } }
static void vmBus_send(String msg, Object... args) {
  Object arg = vmBus_wrapArgs(args);
  pcallFAll(vm_busListeners_live(), msg, arg);
  pcallFAll(vm_busListenersByMessage_live().get(msg), msg, arg);
}

static void vmBus_send(String msg) {
  vmBus_send(msg, (Object) null);
}


static ThreadLocal<Object> print_byThread() {
  synchronized(print_byThread_lock) {
    if (print_byThread == null)
      print_byThread = new ThreadLocal();
  }
  return print_byThread;
}
// f can return false to suppress regular printing
// call print_raw within f to actually print something
static AutoCloseable tempInterceptPrint(F1<String, Boolean> f) {
  return tempSetThreadLocal(print_byThread(), f);
}
static int max(int a, int b) { return Math.max(a, b); }
static int max(int a, int b, int c) { return max(max(a, b), c); }
static long max(int a, long b) { return Math.max((long) a, b); }
static long max(long a, long b) { return Math.max(a, b); }
static double max(int a, double b) { return Math.max((double) a, b); }
static float max(float a, float b) { return Math.max(a, b); }
static double max(double a, double b) { return Math.max(a, b); }

static int max(Collection<Integer> c) {
  int x = Integer.MIN_VALUE;
  for (int i : c) x = max(x, i);
  return x;
}

static double max(double[] c) {
  if (c.length == 0) return Double.MIN_VALUE;
  double x = c[0];
  for (int i = 1; i < c.length; i++) x = Math.max(x, c[i]);
  return x;
}

static float max(float[] c) {
  if (c.length == 0) return Float.MAX_VALUE;
  float x = c[0];
  for (int i = 1; i < c.length; i++) x = Math.max(x, c[i]);
  return x;
}

static byte max(byte[] c) {
  byte x = -128;
  for (byte d : c) if (d > x) x = d;
  return x;
}

static short max(short[] c) {
  short x = -0x8000;
  for (short d : c) if (d > x) x = d;
  return x;
}

static int max(int[] c) {
  int x = Integer.MIN_VALUE;
  for (int d : c) if (d > x) x = d;
  return x;
}
static <A, B> Map<A, B> newDangerousWeakHashMap() {
  return _registerDangerousWeakMap(synchroMap(new WeakHashMap()));
}

// initFunction: voidfunc(Map) - is called initially, and after clearing the map
static <A, B> Map<A, B> newDangerousWeakHashMap(Object initFunction) {
  return _registerDangerousWeakMap(synchroMap(new WeakHashMap()), initFunction);
}
static Object callMCWithVarArgs(String method, Object... args) {
  return call_withVarargs(mc(), method, args);
}
static Object invokeMethod(Method m, Object o, Object... args) { try {
  try {
    return m.invoke(o, args);
  } catch (InvocationTargetException e) {
    throw rethrow(getExceptionCause(e));
  } catch (IllegalArgumentException e) {
    throw new IllegalArgumentException(e.getMessage() + " - was calling: " + m + ", args: " + joinWithSpace(classNames(args)));
  }
} catch (Exception __e) { throw rethrow(__e); } }
static boolean call_checkArgs(Method m, Object[] args, boolean debug) {
  Class<?>[] types = m.getParameterTypes();
  if (types.length != args.length) {
    if (debug)
      print("Bad parameter length: " + args.length + " vs " + types.length);
    return false;
  }
  for (int i = 0; i < types.length; i++) {
    Object arg = args[i];
    if (!(arg == null ? !types[i].isPrimitive()
      : isInstanceX(types[i], arg))) {
      if (debug)
        print("Bad parameter " + i + ": " + arg + " vs " + types[i]);
      return false;
    }
  }
  return true;
}
static final Map<Class, _MethodCache> callOpt_cache = newDangerousWeakHashMap();

static Object callOpt_cached(Object o, String methodName, Object... args) { try {
  if (o == null) return null;
  
  if (o instanceof Class) {
    Class c = (Class) o;
    _MethodCache cache = callOpt_getCache(c);
    
    // TODO: (super-rare) case where method exists static and non-static
    // with different args
    
    Method me = cache.findMethod(methodName, args);
    if (me == null || (me.getModifiers() & Modifier.STATIC) == 0) return null;
    return invokeMethod(me, null, args);
  } else {
    Class c = o.getClass();
    _MethodCache cache = callOpt_getCache(c);

    Method me = cache.findMethod(methodName, args);
    if (me == null) return null;
    return invokeMethod(me, o, args);
  }
} catch (Exception __e) { throw rethrow(__e); } }

static _MethodCache callOpt_getCache(Class c) {
  synchronized(callOpt_cache) {
    _MethodCache cache = callOpt_cache.get(c);
    if (cache == null)
      callOpt_cache.put(c, cache = new _MethodCache(c));
    return cache;
  }
}
static boolean isStaticMethod(Method m) {
  return methodIsStatic(m);
}
static Object[] massageArgsForVarArgsCall(Method m, Object[] args) {
  Class<?>[] types = m.getParameterTypes();
  int n = types.length-1, nArgs = args.length;
  if (nArgs < n) return null;
  for (int i = 0; i < n; i++)
    if (!argumentCompatibleWithType(args[i], types[i]))
      return null;
  Class varArgType = types[n].getComponentType();
  for (int i = n; i < nArgs; i++)
    if (!argumentCompatibleWithType(args[i], varArgType))
      return null;
  Object[] newArgs = new Object[n+1];
  arraycopy(args, 0, newArgs, 0, n);
  Object[] varArgs = arrayOfType(varArgType, nArgs-n);
  arraycopy(args, n, varArgs, 0, nArgs-n);
  newArgs[n] = varArgs;
  return newArgs;
}
static <A> String joinWithComma(Collection<A> c) {
  return join(", ", c);
}

static String joinWithComma(String... c) {
  return join(", ", c);
}


static String joinWithComma(Pair p) {
  return p == null ? "" : joinWithComma(str(p.a), str(p.b));
}

static List<String> classNames(Collection l) {
  return getClassNames(l);
}

static List<String> classNames(Object[] l) {
  return getClassNames(Arrays.asList(l));
}
static Class javax() {
  return getJavaX();
}



//sbool ping_actions_shareable = true;
static volatile boolean ping_pauseAll = false;
static int ping_sleep = 100; // poll pauseAll flag every 100
static volatile boolean ping_anyActions = false;
static Map<Thread, Object> ping_actions = newWeakHashMap();
static ThreadLocal<Boolean> ping_isCleanUpThread = new ThreadLocal();

// always returns true
static boolean ping() {
  if (ping_pauseAll || ping_anyActions) ping_impl(true /* XXX */);
  //ifndef LeanMode ping_impl(); endifndef
  return true;
}

// returns true when it slept
static boolean ping_impl(boolean okInCleanUp) { try {
  if (ping_pauseAll && !isAWTThread()) {
    do
      Thread.sleep(ping_sleep);
    while (ping_pauseAll);
    return true;
  }
  
  if (ping_anyActions) { // don't allow sharing ping_actions
    if (!okInCleanUp && !isTrue(ping_isCleanUpThread.get()))
      failIfUnlicensed();
    Object action = null;
    synchronized(ping_actions) {
      if (!ping_actions.isEmpty()) {
        action = ping_actions.get(currentThread());
        if (action instanceof Runnable)
          ping_actions.remove(currentThread());
        if (ping_actions.isEmpty()) ping_anyActions = false;
      }
    }
    
    if (action instanceof Runnable)
      ((Runnable) action).run();
    else if (eq(action, "cancelled"))
      throw fail("Thread cancelled.");
  }

  return false;
} catch (Exception __e) { throw rethrow(__e); } }

static Object getOpt(Object o, String field) {
  return getOpt_cached(o, field);
}

static Object getOpt(String field, Object o) {
  return getOpt_cached(o, field);
}

static Object getOpt_raw(Object o, String field) { try {
  Field f = getOpt_findField(o.getClass(), field);
  if (f == null) return null;
  makeAccessible(f);
  return f.get(o);
} catch (Exception __e) { throw rethrow(__e); } }

// access of static fields is not yet optimized
static Object getOpt(Class c, String field) { try {
  if (c == null) return null;
  Field f = getOpt_findStaticField(c, field);
  if (f == null) return null;
  makeAccessible(f);
  return f.get(null);
} catch (Exception __e) { throw rethrow(__e); } }

static Field getOpt_findStaticField(Class<?> c, String field) {
  Class _c = c;
  do {
    for (Field f : _c.getDeclaredFields())
      if (f.getName().equals(field) && (f.getModifiers() & java.lang.reflect.Modifier.STATIC) != 0)
        return f;
    _c = _c.getSuperclass();
  } while (_c != null);
  return null;
}

static <A> A or(A a, A b) {
  return a != null ? a : b;
}
static <A> int indexOf(List<A> l, A a, int startIndex) {
  if (l == null) return -1;
  int n = l(l);
  for (int i = startIndex; i < n; i++)
    if (eq(l.get(i), a))
      return i;
  return -1;
}

static <A> int indexOf(List<A> l, int startIndex, A a) {
  return indexOf(l, a, startIndex);
}

static <A> int indexOf(List<A> l, A a) {
  if (l == null) return -1;
  return l.indexOf(a);
}

static int indexOf(String a, String b) {
  return a == null || b == null ? -1 : a.indexOf(b);
}

static int indexOf(String a, String b, int i) {
  return a == null || b == null ? -1 : a.indexOf(b, i);
}

static int indexOf(String a, char b) {
  return a == null ? -1 : a.indexOf(b);
}

static int indexOf(String a, int i, char b) {
  return indexOf(a, b, i);
}

static int indexOf(String a, char b, int i) {
  return a == null ? -1 : a.indexOf(b, i);
}

static int indexOf(String a, int i, String b) {
  return a == null || b == null ? -1 : a.indexOf(b, i);
}

static <A> int indexOf(A[] x, A a) {
  int n = l(x);
  for (int i = 0; i < n; i++)
    if (eq(x[i], a))
      return i;
  return -1;
}
static void rotateStringBuffer(StringBuffer buf, int max) { try {
  if (buf == null) return;
  synchronized(buf) {
    if (buf.length() <= max) return;
    
    try {
      int newLength = max/2;
      int ofs = buf.length()-newLength;
      String newString = buf.substring(ofs);
      buf.setLength(0);
      buf.append("[...] ").append(newString);
    } catch (Exception e) {
      buf.setLength(0);
    }
    buf.trimToSize();
  }
} catch (Exception __e) { throw rethrow(__e); } }
static void rotateStringBuilder(StringBuilder buf, int max) { try {
  if (buf == null) return;
  synchronized(buf) {
    if (buf.length() <= max) return;
    
    try {
      int newLength = max/2;
      int ofs = buf.length()-newLength;
      String newString = buf.substring(ofs);
      buf.setLength(0);
      buf.append("[...] ").append(newString);
    } catch (Exception e) {
      buf.setLength(0);
    }
    buf.trimToSize();
  }
} catch (Exception __e) { throw rethrow(__e); } }
static Object vmBus_wrapArgs(Object... args) {
  return empty(args) ? null
    : l(args) == 1 ? args[0]
    : args;
}
static void pcallFAll(Collection l, Object... args) {
  if (l != null) for (Object f : cloneList(l)) pcallF(f, args);
}

static void pcallFAll(Iterator it, Object... args) {
  while (it.hasNext()) pcallF(it.next(), args);
}
static Set vm_busListeners_live_cache;
static Set vm_busListeners_live() { if (vm_busListeners_live_cache == null) vm_busListeners_live_cache = vm_busListeners_live_load(); return vm_busListeners_live_cache; }

static Set vm_busListeners_live_load() {
  return vm_generalIdentityHashSet("busListeners");
}
static Map<String, Set> vm_busListenersByMessage_live_cache;
static Map<String, Set> vm_busListenersByMessage_live() { if (vm_busListenersByMessage_live_cache == null) vm_busListenersByMessage_live_cache = vm_busListenersByMessage_live_load(); return vm_busListenersByMessage_live_cache; }

static Map<String, Set> vm_busListenersByMessage_live_load() {
  return vm_generalHashMap("busListenersByMessage");
}


static <A> AutoCloseable tempSetThreadLocal(final ThreadLocal<A> tl, A a) {
  if (tl == null) return null;
  final A prev = setThreadLocal(tl, a);
  return new AutoCloseable() { public String toString() { return "tl.set(prev);"; } public void close() throws Exception { tl.set(prev); }};
}
static List<Pair> _registerDangerousWeakMap_preList;

static <A> A _registerDangerousWeakMap(A map) {
  return _registerDangerousWeakMap(map, null);
}

static <A> A _registerDangerousWeakMap(A map, Object init) {
  
  callF(init, map);
  
  if (init instanceof String) {
    final String f =  (String) init;
    init = new VF1<Map>() { public void get(Map map) { try {  callMC(f, map) ; } catch (Exception __e) { throw rethrow(__e); } }
  public String toString() { return "callMC(f, map)"; }};
  }
    
  if (javax() == null) {
    // We're in class init
    if (_registerDangerousWeakMap_preList == null) _registerDangerousWeakMap_preList = synchroList();
    _registerDangerousWeakMap_preList.add(pair(map, init));
    return map;
  }
  
  call(javax(), "_registerDangerousWeakMap", map, init);
  
  return map;
}

static void _onLoad_registerDangerousWeakMap() {
  
  assertNotNull(javax());
  if (_registerDangerousWeakMap_preList == null) return;
  for (Pair p : _registerDangerousWeakMap_preList)
    _registerDangerousWeakMap(p.a, p.b);
  _registerDangerousWeakMap_preList = null;
  
}
static Map synchroMap() {
  return synchroHashMap();
}

static <A, B> Map<A, B> synchroMap(Map<A, B> map) {
  return Collections.synchronizedMap(map);
}
static Class mc() {
  return main.class;
}
static Throwable getExceptionCause(Throwable e) {
  Throwable c = e.getCause();
  return c != null ? c : e;
}
static String joinWithSpace(Iterable c) {
  return join(" ", c);
}

static String joinWithSpace(String... c) {
  return join(" ", c);
}

static boolean isInstanceX(Class type, Object arg) {
  if (type == boolean.class) return arg instanceof Boolean;
  if (type == int.class) return arg instanceof Integer;
  if (type == long.class) return arg instanceof Long;
  if (type == float.class) return arg instanceof Float;
  if (type == short.class) return arg instanceof Short;
  if (type == char.class) return arg instanceof Character;
  if (type == byte.class) return arg instanceof Byte;
  if (type == double.class) return arg instanceof Double;
  return type.isInstance(arg);
}
static boolean methodIsStatic(Method m) {
  return (m.getModifiers() & Modifier.STATIC) != 0;
}
static boolean argumentCompatibleWithType(Object arg, Class type) {
  return arg == null ? !type.isPrimitive() : isInstanceX(type, arg);
}
static void arraycopy(Object[] a, Object[] b) {
  if (a != null && b != null)
    arraycopy(a, 0, b, 0, Math.min(a.length, b.length));
}

static void arraycopy(Object src, int srcPos, Object dest, int destPos, int n) {
  if (n != 0)
    System.arraycopy(src, srcPos, dest, destPos, n);
}
static <A> A[] arrayOfType(Class<A> type, int n) {
  return makeArray(type, n);
}

static <A> A[] arrayOfType(int n, Class<A> type) {
  return arrayOfType(type, n);
}
public static <A> String join(String glue, Iterable<A> strings) {
  if (strings == null) return "";
  if (strings instanceof Collection) {
    if (((Collection) strings).size() == 1) return str(first(((Collection) strings)));
  }
  StringBuilder buf = new StringBuilder();
  Iterator<A> i = strings.iterator();
  if (i.hasNext()) {
    buf.append(i.next());
    while (i.hasNext())
      buf.append(glue).append(i.next());
  }
  return buf.toString();
}

public static String join(String glue, String... strings) {
  return join(glue, Arrays.asList(strings));
}

static <A> String join(Iterable<A> strings) {
  return join("", strings);
}

static <A> String join(Iterable<A> strings, String glue) {
  return join(glue, strings);
}

public static String join(String[] strings) {
  return join("", strings);
}


static String join(String glue, Pair p) {
  return p == null ? "" : str(p.a) + glue + str(p.b);
}

static List<String> getClassNames(Collection l) {
  List<String> out = new ArrayList();
  if (l != null) for (Object o : l)
    out.add(o == null ? null : getClassName(o));
  return out;
}
static Class __javax;

static Class getJavaX() { try {
  
  return __javax;
} catch (Exception __e) { throw rethrow(__e); } }
static <A, B> Map<A, B> newWeakHashMap() {
  return _registerWeakMap(synchroMap(new WeakHashMap()));
}
// TODO: test if android complains about this
static boolean isAWTThread() {
  if (isAndroid()) return false;
  if (isHeadless()) return false;
  return isAWTThread_awt();
}

static boolean isAWTThread_awt() {
  return SwingUtilities.isEventDispatchThread();
}
static void failIfUnlicensed() {
  assertTrue("license off", licensed());
}
static Thread currentThread() {
  return Thread.currentThread();
}
//static final Map<Class, HashMap<S, Field>> getOpt_cache = newDangerousWeakHashMap(f getOpt_special_init);

static class getOpt_Map extends WeakHashMap {
  getOpt_Map() {
    if (getOpt_special == null) getOpt_special = new HashMap();
    clear();
  }
  
  public void clear() {
    super.clear();
    //print("getOpt clear");
    put(Class.class, getOpt_special);
    put(String.class, getOpt_special);
  }
}

static final Map<Class, HashMap<String, Field>> getOpt_cache = _registerDangerousWeakMap(synchroMap(new getOpt_Map()));
//static final Map<Class, HashMap<S, Field>> getOpt_cache = _registerWeakMap(synchroMap(new getOpt_Map));
static HashMap getOpt_special; // just a marker

/*static void getOpt_special_init(Map map) {
  map.put(Class.class, getOpt_special);
  map.put(S.class, getOpt_special);
}*/

static Object getOpt_cached(Object o, String field) { try {
  if (o == null) return null;

  Class c = o.getClass();
  HashMap<String, Field> map;
  synchronized(getOpt_cache) {
    map = getOpt_cache.get(c);
    if (map == null)
      map = getOpt_makeCache(c);
  }
  
  if (map == getOpt_special) {
    if (o instanceof Class)
      return getOpt((Class) o, field);
    /*if (o instanceof S)
      ret getOpt(getBot((S) o), field);*/
    if (o instanceof Map)
      return ((Map) o).get(field);
  }
    
  Field f = map.get(field);
  if (f != null) return f.get(o);
  
  return null;
} catch (Exception __e) { throw rethrow(__e); } }

// used internally - we are in synchronized block
static HashMap<String, Field> getOpt_makeCache(Class c) {
  HashMap<String, Field> map;
  if (isSubtypeOf(c, Map.class))
    map = getOpt_special;
  else {
    map = new HashMap();
    if (!reflection_classesNotToScan().contains(c.getName())) {
      Class _c = c;
      do {
        for (Field f : _c.getDeclaredFields()) {
          makeAccessible(f);
          String name = f.getName();
          if (!map.containsKey(name))
            map.put(name, f);
        }
        _c = _c.getSuperclass();
      } while (_c != null);
    }
  }
  if (getOpt_cache != null) getOpt_cache.put(c, map);
  return map;
}
static <A> ArrayList<A> cloneList(Iterable<A> l) {
  return l instanceof Collection ? cloneList((Collection) l) : asList(l);
}

static <A> ArrayList<A> cloneList(Collection<A> l) {
  if (l == null) return new ArrayList();
  synchronized(collectionMutex(l)) {
    return new ArrayList<A>(l);
  }
}
static Object pcallF(Object f, Object... args) {
  return pcallFunction(f, args);
}




static <A, B> B pcallF(F1<A, B> f, A a) { try {
  return f == null ? null : f.get(a);
} catch (Throwable __e) { return null; } }



static <A> void pcallF(VF1<A> f, A a) {
  try {
    if (f != null) f.get(a);
  } catch (Throwable __e) { _handleException(__e); }
}

static Set vm_generalIdentityHashSet(Object name) {
  synchronized(get(javax(), "generalMap")) {
    Set set =  (Set) (vm_generalMap_get(name));
    if (set == null)
      vm_generalMap_put(name, set = syncIdentityHashSet());
    return set;
  }
}

static Map vm_generalHashMap(Object name) {
  synchronized(get(javax(), "generalMap")) {
    Map m =  (Map) (vm_generalMap_get(name));
    if (m == null)
      vm_generalMap_put(name, m = syncHashMap());
    return m;
  }
}



static <A> A setThreadLocal(ThreadLocal<A> tl, A value) {
  if (tl == null) return null;
  A old = tl.get();
  tl.set(value);
  return old;
}
static HashMap<String, List<Method>> callMC_cache = new HashMap();
static String callMC_key;
static Method callMC_value;

// varargs assignment fixer for a single string array argument
static Object callMC(String method, String[] arg) {
  return callMC(method, new Object[] {arg});
}

static Object callMC(String method, Object... args) { try {
  Method me;
  if (callMC_cache == null) callMC_cache = new HashMap(); // initializer time workaround
  synchronized(callMC_cache) {
    me = method == callMC_key ? callMC_value : null;
  }
  if (me != null) try {
    return invokeMethod(me, null, args);
  } catch (IllegalArgumentException e) {
    throw new RuntimeException("Can't call " + me + " with arguments " + classNames(args), e);
  }

  List<Method> m;
  synchronized(callMC_cache) {
    m = callMC_cache.get(method);
  }
  if (m == null) {
    if (callMC_cache.isEmpty()) {
      callMC_makeCache();
      m = callMC_cache.get(method);
    }
    if (m == null) throw fail("Method named " + method + " not found in main");
  }
  int n = m.size();
  if (n == 1) {
    me = m.get(0);
    synchronized(callMC_cache) {
      callMC_key = method;
      callMC_value = me;
    }
    try {
      return invokeMethod(me, null, args);
    } catch (IllegalArgumentException e) {
      throw new RuntimeException("Can't call " + me + " with arguments " + classNames(args), e);
    }
  }
  for (int i = 0; i < n; i++) {
    me = m.get(i);
    if (call_checkArgs(me, args, false))
      return invokeMethod(me, null, args);
  }
  throw fail("No method called " + method + " with arguments (" + joinWithComma(getClasses(args)) + ") found in main");
} catch (Exception __e) { throw rethrow(__e); } }

static void callMC_makeCache() {
  synchronized(callMC_cache) {
    callMC_cache.clear();
    Class _c = (Class) mc(), c = _c;
    while (c != null) {
      for (Method m : c.getDeclaredMethods())
        if ((m.getModifiers() & java.lang.reflect.Modifier.STATIC) != 0) {
          makeAccessible(m);
          multiMapPut(callMC_cache, m.getName(), m);
        }
      c = c.getSuperclass();
    }
  }
}
static <A> List<A> synchroList() {
  return Collections.synchronizedList(new ArrayList<A>());
}

static <A> List<A> synchroList(List<A> l) {
  return Collections.synchronizedList(l);
}

static <A, B> Pair<A, B> pair(A a, B b) {
  return new Pair(a, b);
}

static <A> Pair<A, A> pair(A a) {
  return new Pair(a, a);
}
static <A> A assertNotNull(A a) {
  assertTrue(a != null);
  return a;
}

static <A> A assertNotNull(String msg, A a) {
  assertTrue(msg, a != null);
  return a;
}
static Map synchroHashMap() {
  return Collections.synchronizedMap(new HashMap());
}

static <A> A[] makeArray(Class<A> type, int n) {
  return (A[]) Array.newInstance(type, n);
}

static Object first(Object list) {
  return first((Iterable) list);
}


static <A> A first(List<A> list) {
  return empty(list) ? null : list.get(0);
}

static <A> A first(A[] bla) {
  return bla == null || bla.length == 0 ? null : bla[0];
}



static <A> A first(Iterator<A> i) {
  return i == null || !i.hasNext() ? null : i.next();
}

static <A> A first(Iterable<A> i) {
  if (i == null) return null;
  Iterator<A> it = i.iterator();
  return it.hasNext() ? it.next() : null;
}

static Character first(String s) { return empty(s) ? null : s.charAt(0); }
static Character first(CharSequence s) { return empty(s) ? null : s.charAt(0); }


static <A, B> A first(Pair<A, B> p) {
  return p == null ? null : p.a;
}




static Byte first(byte[] l) { 
  return empty(l) ? null : l[0];
}


static List _registerWeakMap_preList;

static <A> A _registerWeakMap(A map) {
  if (javax() == null) {
    // We're in class init
    if (_registerWeakMap_preList == null) _registerWeakMap_preList = synchroList();
    _registerWeakMap_preList.add(map);
    return map;
  }
  
  try {
    call(javax(), "_registerWeakMap", map);
  } catch (Throwable e) {
    printException(e);
    print("Upgrade JavaX!!");
  }
  return map;
}

static void _onLoad_registerWeakMap() {
  assertNotNull(javax());
  if (_registerWeakMap_preList == null) return;
  for (Object o : _registerWeakMap_preList)
    _registerWeakMap(o);
  _registerWeakMap_preList = null;
}
static int isAndroid_flag;

static boolean isAndroid() {
  if (isAndroid_flag == 0)
    isAndroid_flag = System.getProperty("java.vendor").toLowerCase().indexOf("android") >= 0 ? 1 : -1;
  return isAndroid_flag > 0;
}

static Boolean isHeadless_cache;

static boolean isHeadless() {
  if (isHeadless_cache != null) return isHeadless_cache;
  if (isAndroid()) return isHeadless_cache = true;
  if (GraphicsEnvironment.isHeadless()) return isHeadless_cache = true;
  
  // Also check if AWT actually works.
  // If DISPLAY variable is set but no X server up, this will notice.
  
  try {
    SwingUtilities.isEventDispatchThread();
    return isHeadless_cache = false;
  } catch (Throwable e) { return isHeadless_cache = true; }
}
static void assertTrue(Object o) {
  if (!(eq(o, true) /*|| isTrue(pcallF(o))*/))
    throw fail(str(o));
}
  
static boolean assertTrue(String msg, boolean b) {
  if (!b)
    throw fail(msg);
  return b;
}

static boolean assertTrue(boolean b) {
  if (!b)
    throw fail("oops");
  return b;
}
static volatile boolean licensed_yes = true;

static boolean licensed() {
  if (!licensed_yes) return false;
  ping_okInCleanUp();
  return true;
}

static void licensed_off() {
  licensed_yes = false;
}
static void clear(Collection c) {
  if (c != null) c.clear();
}

static void clear(Map map) {
  if (map != null) map.clear();
}
static <A, B> void put(Map<A, B> map, A a, B b) {
  if (map != null) map.put(a, b);
}

static <A> void put(List<A> l, int i, A a) {
  if (l != null && i >= 0 && i < l(l)) l.set(i, a);
}
static <A, B> B mapGet2(Map<A, B> map, A a) {
  return map == null ? null : map.get(a);
}

static <A, B> B mapGet2(A a, Map<A, B> map) {
  return map == null ? null : map.get(a);
}
static boolean isSubtypeOf(Class a, Class b) {
  return b.isAssignableFrom(a); // << always hated that method, let's replace it!
}
static Set<String> reflection_classesNotToScan_value = litset(
  "jdk.internal.loader.URLClassPath"
);

static Set<String> reflection_classesNotToScan() {
  return reflection_classesNotToScan_value;
}
static Object collectionMutex(List l) {
  return l;
}

static Object collectionMutex(Object o) {
  if (o instanceof List) return o;
  
  String c = className(o);
  if (eq(c, "java.util.TreeMap$KeySet"))
    c = className(o = getOpt(o, "m"));
  else if (eq(c, "java.util.HashMap$KeySet"))
    c = className(o = get_raw(o, "this$0"));

  
  
  if (eqOneOf(c, "java.util.TreeMap$AscendingSubMap", "java.util.TreeMap$DescendingSubMap"))
    c = className(o = get_raw(o, "m"));
    
  
    
  return o;
}
static Object pcallFunction(Object f, Object... args) {
  try { return callFunction(f, args); } catch (Throwable __e) { _handleException(__e); }
  return null;
}
static volatile PersistableThrowable _handleException_lastException;
static List _handleException_onException = synchroList(ll("printStackTrace2"));

static void _handleException(Throwable e) {
  _handleException_lastException = persistableThrowable(e);
  
  Throwable e2 = innerException(e);
  if (e2.getClass() == RuntimeException.class && eq(e2.getMessage(), "Thread cancelled.") || e2 instanceof InterruptedException)
    return;
    
  for (Object f : cloneList(_handleException_onException)) try {
    callF(f, e);
  } catch (Throwable e3) {
    printStackTrace2(e3); // not using pcall here - it could lead to endless loops
  }
}

static Object vm_generalMap_get(Object key) {
  return vm_generalMap().get(key);
}
static Object vm_generalMap_put(Object key, Object value) {
  return mapPutOrRemove(vm_generalMap(), key, value);
}
static <A> Set<A> syncIdentityHashSet() {
  return (Set) synchronizedSet(identityHashSet());
}
static Map syncHashMap() {
  return synchroHashMap();
}


static Throwable printStackTrace2(Throwable e) {
  // we go to system.out now - system.err is nonsense
  print(getStackTrace2(e));
  return e;
}

static void printStackTrace2() {
  printStackTrace2(new Throwable());
}

static void printStackTrace2(String msg) {
  printStackTrace2(new Throwable(msg));
}

static List<Class> getClasses(Object[] array) {
  List<Class> l = emptyList(l(array));
  for (Object o : array) l.add(_getClass(o));
  return l;
}
static <A, B> void multiMapPut(Map<A, List<B>> map, A a, B b) {
  List<B> l = map.get(a);
  if (l == null)
    map.put(a, l = new ArrayList());
  l.add(b);
}


static <A extends Throwable> A printException(A e) {
  printStackTrace(e);
  return e;
}
static <A> HashSet<A> litset(A... items) {
  return lithashset(items);
}
static String className(Object o) {
  return getClassName(o);
}
static boolean eqOneOf(Object o, Object... l) {
  for (Object x : l) if (eq(o, x)) return true; return false;
}
static Object callFunction(Object f, Object... args) {
  return callF(f, args);
}
static <A> List<A> ll(A... a) {
  ArrayList l = new ArrayList(a.length);
  if (a != null) for (A x : a) l.add(x);
  return l;
}
static PersistableThrowable persistableThrowable(Throwable e) {
  return e == null ? null : new PersistableThrowable(e);
}
static Throwable innerException(Throwable e) {
  return getInnerException(e);
}
static Map vm_generalMap_map;

static Map vm_generalMap() {
  if (vm_generalMap_map == null)
    vm_generalMap_map = (Map) get(javax(), "generalMap");
  return vm_generalMap_map;
}
static <A, B> B mapPutOrRemove(Map<A, B> map, A key, B value) {
  if (map != null && key != null)
    if (value != null) return map.put(key, value);
    else return map.remove(key);
  return null;
}
static <A> Set<A> synchronizedSet() {
  return synchroHashSet();
}

static <A> Set<A> synchronizedSet(Set<A> set) {
  return Collections.synchronizedSet(set);
}
static <A> Set<A> identityHashSet() {
  return Collections.newSetFromMap(new IdentityHashMap());
}


static String getStackTrace2(Throwable e) {
  return hideCredentials(getStackTrace(unwrapTrivialExceptionWraps(e)) + replacePrefix("java.lang.RuntimeException: ", "FAIL: ",
    hideCredentials(str(innerException2(e)))) + "\n");
}
static Class<?> _getClass(String name) {
  try {
    return Class.forName(name);
  } catch (ClassNotFoundException e) {
    return null; // could optimize this
  }
}

static Class _getClass(Object o) {
  return o == null ? null
    : o instanceof Class ? (Class) o : o.getClass();
}

static Class _getClass(Object realm, String name) {
  try {
    return getClass(realm).getClassLoader().loadClass(classNameToVM(name));
  } catch (ClassNotFoundException e) {
    return null; // could optimize this
  }
}
static <A extends Throwable> A printStackTrace(A e) {
  // we go to system.out now - system.err is nonsense
  print(getStackTrace(e));
  return e;
}

static void printStackTrace() {
  printStackTrace(new Throwable());
}

static void printStackTrace(String msg) {
  printStackTrace(new Throwable(msg));
}

static void printStackTrace(String msg, Throwable e) {
  printStackTrace(new Throwable(msg, e));
}
static <A> HashSet<A> lithashset(A... items) {
  HashSet<A> set = new HashSet();
  for (A a : items) set.add(a);
  return set;
}
static Throwable getInnerException(Throwable e) {
  if (e == null) return null;
  while (e.getCause() != null)
    e = e.getCause();
  return e;
}

static Throwable getInnerException(Runnable r) {
  return getInnerException(getException(r));
}
static <A> Set<A> synchroHashSet() {
  return Collections.synchronizedSet(new HashSet<A>());
}



static String hideCredentials(URL url) { return url == null ? null : hideCredentials(str(url)); }

static String hideCredentials(String url) {
  try {
    if (startsWithOneOf(url, "http://", "https://") && isAGIBlueDomain(hostNameFromURL(url))) return url;
  } catch (Throwable e) {
    print("HideCredentials", e);
  }
  return url.replaceAll("([&?])(_pass|key|cookie)=[^&\\s\"]*", "$1$2=<hidden>");
}

static String hideCredentials(Object o) {
  return hideCredentials(str(o));
}
static String getStackTrace(Throwable throwable) {
  lastException(throwable);
  return getStackTrace_noRecord(throwable);
}

static String getStackTrace_noRecord(Throwable throwable) {
  StringWriter writer = new StringWriter();
  throwable.printStackTrace(new PrintWriter(writer));
  return hideCredentials(writer.toString());
}

static String getStackTrace() {
  return getStackTrace_noRecord(new Throwable());
}
static Throwable unwrapTrivialExceptionWraps(Throwable e) {
  if (e == null) return e;
  while (e.getClass() == RuntimeException.class
    && e.getCause() != null && eq(e.getMessage(), str(e.getCause())))
    e = e.getCause();
  return e;
}
static String replacePrefix(String prefix, String replacement, String s) {
  if (!startsWith(s, prefix)) return s;
  return replacement + substring(s, l(prefix));
}
static Throwable innerException2(Throwable e) {
  if (e == null) return null;
  while (empty(e.getMessage()) && e.getCause() != null)
    e = e.getCause();
  return e;
}
static Class<?> getClass(String name) {
  try {
    return Class.forName(name);
  } catch (ClassNotFoundException e) {
    return null;
  }
}

static Class getClass(Object o) {
  return o instanceof Class ? (Class) o : o.getClass();
}

static Class getClass(Object realm, String name) { try {
  try {
    return getClass(realm).getClassLoader().loadClass(classNameToVM(name));
  } catch (ClassNotFoundException e) {
    return null;
  }
} catch (Exception __e) { throw rethrow(__e); } }
static String classNameToVM(String name) {
  return name.replace(".", "$");
}
static Throwable getException(Runnable r) {
  try {
    callF(r);
    return null;
  } catch (Throwable e) {
    return e;
  }
}


static boolean startsWithOneOf(String s, String... l) {
  for (String x : l) if (startsWith(s, x)) return true; return false;
}

static boolean startsWithOneOf(String s, Matches m, String... l) {
  for (String x : l) if (startsWith(s, x, m)) return true; return false;
}
static boolean isAGIBlueDomain(String domain) {
  return domainIsUnder(domain, theAGIBlueDomain());
}
static String hostNameFromURL(String url) { try {
  return new URL(url).getHost();
} catch (Exception __e) { throw rethrow(__e); } }
// PersistableThrowable doesn't hold GC-disturbing class references in backtrace
static volatile PersistableThrowable lastException_lastException;

static PersistableThrowable lastException() {
  return lastException_lastException;
}

static void lastException(Throwable e) {
  lastException_lastException = persistableThrowable(e);
}
static boolean startsWith(String a, String b) {
  return a != null && a.startsWith(unnull(b));
}

static boolean startsWith(String a, char c) {
  return nemptyString(a) && a.charAt(0) == c;
}


  static boolean startsWith(String a, String b, Matches m) {
    if (!startsWith(a, b)) return false;
    m.m = new String[] {substring(a, strL(b))};
    return true;
  }


static boolean startsWith(List a, List b) {
  if (a == null || listL(b) > listL(a)) return false;
  for (int i = 0; i < listL(b); i++)
    if (neq(a.get(i), b.get(i)))
      return false;
  return true;
}


static String substring(String s, int x) {
  return substring(s, x, strL(s));
}

static String substring(String s, int x, int y) {
  if (s == null) return null;
  if (x < 0) x = 0;
  int n = s.length();
  if (y < x) y = x;
  if (y > n) y = n;
  if (x >= y) return "";
  return s.substring(x, y);
}



// convenience method for quickly dropping a prefix
static String substring(String s, CharSequence l) {
  return substring(s, l(l));
}


static boolean domainIsUnder(String domain, String mainDomain) {
  return eqic(domain, mainDomain) || ewic(domain, "." + mainDomain);
}
static String theAGIBlueDomain() {
  return "agi.blue";
}
static String unnull(String s) {
  return s == null ? "" : s;
}

static <A> Collection<A> unnull(Collection<A> l) {
  return l == null ? emptyList() : l;
}

static <A> List<A> unnull(List<A> l) { return l == null ? emptyList() : l; }
static int[] unnull(int[] l) { return l == null ? emptyIntArray() : l; }
static char[] unnull(char[] l) { return l == null ? emptyCharArray() : l; }

static <A, B> Map<A, B> unnull(Map<A, B> l) {
  return l == null ? emptyMap() : l;
}

static <A> Iterable<A> unnull(Iterable<A> i) {
  return i == null ? emptyList() : i;
}

static <A> A[] unnull(A[] a) {
  return a == null ? (A[]) emptyObjectArray() : a;
}

static BitSet unnull(BitSet b) {
  return b == null ? new BitSet() : b;
}



//ifclass Symbol



static <A, B> Pair<A, B> unnull(Pair<A, B> p) {
  return p != null ? p : new Pair(null, null);
}

static boolean nemptyString(String s) {
  return s != null && s.length() > 0;
}
static int strL(String s) {
  return s == null ? 0 : s.length();
}
static int listL(Collection l) {
  return l == null ? 0 : l.size();
}
static boolean neq(Object a, Object b) {
  return !eq(a, b);
}


static boolean eqic(String a, String b) {
  
  
    if ((a == null) != (b == null)) return false;
    if (a == null) return true;
    return a.equalsIgnoreCase(b);
  
}



static boolean eqic(char a, char b) {
  if (a == b) return true;
  
    char u1 = Character.toUpperCase(a);
    char u2 = Character.toUpperCase(b);
    if (u1 == u2) return true;
  
  return Character.toLowerCase(u1) == Character.toLowerCase(u2);
}
static boolean ewic(String a, String b) {
  return endsWithIgnoreCase(a, b);
}


static boolean ewic(String a, String b, Matches m) {
  return endsWithIgnoreCase(a, b, m);
}

static int[] emptyIntArray_a = new int[0];
static int[] emptyIntArray() { return emptyIntArray_a; }
static char[] emptyCharArray = new char[0];
static char[] emptyCharArray() { return emptyCharArray; }
static Map emptyMap() {
  return new HashMap();
}
static Object[] emptyObjectArray_a = new Object[0];
static Object[] emptyObjectArray() { return emptyObjectArray_a; }


static String asString(Object o) {
  return o == null ? null : o.toString();
}
static boolean endsWithIgnoreCase(String a, String b) {
  int la = l(a), lb = l(b);
  return la >= lb && regionMatchesIC(a, la-lb, b, 0, lb);
}


static boolean endsWithIgnoreCase(String a, String b, Matches m) {
  if (!endsWithIgnoreCase(a, b)) return false;
  m.m = new String[] { substring(a, 0, l(a)-l(b)) };
  return true;
}



static boolean regionMatchesIC(String a, int offsetA, String b, int offsetB, int len) {
  
  
    return a != null && a.regionMatches(true, offsetA, b, offsetB, len);
  
}


// immutable, has strong refs
final static class _MethodCache {
  final Class c;
  final HashMap<String, List<Method>> cache = new HashMap();
  
  _MethodCache(Class c) {
  this.c = c; _init(); }
  
  void _init() {
    Class _c = c;
    while (_c != null) {
      for (Method m : _c.getDeclaredMethods())
        if (!isAbstract(m) && !reflection_isForbiddenMethod(m))
          multiMapPut(cache, m.getName(), makeAccessible(m));
      _c = _c.getSuperclass();
    }
    
    // add default methods - this might lead to a duplication
    // because the overridden method is also added, but it's not
    // a problem except for minimal performance loss.
    for (Class intf : allInterfacesImplementedBy(c))
      for (Method m : intf.getDeclaredMethods())
        if (m.isDefault() && !reflection_isForbiddenMethod(m))
          multiMapPut(cache, m.getName(), makeAccessible(m));

    
  }
  
  // Returns only matching methods
  Method findMethod(String method, Object[] args) { try {
    List<Method> m = cache.get(method);
    
    if (m == null) return null;
    int n = m.size();
    for (int i = 0; i < n; i++) {
      Method me = m.get(i);
      if (call_checkArgs(me, args, false))
        return me;
    }
    return null;
  } catch (Exception __e) { throw rethrow(__e); } }
  
  Method findStaticMethod(String method, Object[] args) { try {
    List<Method> m = cache.get(method);
    if (m == null) return null;
    int n = m.size();
    for (int i = 0; i < n; i++) {
      Method me = m.get(i);
      if (isStaticMethod(me) && call_checkArgs(me, args, false))
        return me;
    }
    return null;
  } catch (Exception __e) { throw rethrow(__e); } }
}static abstract class VF1<A> implements IVF1<A> {
  public abstract void get(A a);
}static class Matches {
  String[] m;
  
  Matches() {}
  Matches(String... m) {
  this.m = m;}
  
  String get(int i) { return i < m.length ? m[i] : null; }
  String unq(int i) { return unquote(get(i)); }
  
  String tlc(int i) { return unq(i).toLowerCase(); }
  boolean bool(int i) { return "true".equals(unq(i)); }
  String rest() { return m[m.length-1]; } // for matchStart
  int psi(int i) { return Integer.parseInt(unq(i)); }
  
  public String toString() { return "Matches(" + joinWithComma(quoteAll(asList(m))) + ")"; }
  
  public int hashCode() { return _hashCode(toList(m)); }
  public boolean equals(Object o) { return o instanceof Matches && arraysEqual(m, ((Matches) o).m); }
}
static class PersistableThrowable {
  String className;
  String msg;
  String stacktrace;
  
  PersistableThrowable() {}
  PersistableThrowable(Throwable e) {
    if (e == null)
      className = "Crazy Null Error";
    else {
      className = getClassName(e).replace('/', '.');
      msg = e.getMessage();
      stacktrace = getStackTrace_noRecord(e);
    }
  }
  
  public String toString() {
    return nempty(msg) ? className + ": " + msg : className;
  }
}static interface IF0_Byte {
  byte get();
}static abstract class F1<A, B> {
  abstract B get(A a);
}static class Pair<A, B> implements Comparable<Pair<A, B>> {
  A a;
  B b;

  Pair() {}
  Pair(A a, B b) {
  this.b = b;
  this.a = a;}
  
  public int hashCode() {
    return hashCodeFor(a) + 2*hashCodeFor(b);
  }
  
  public boolean equals(Object o) {
    if (o == this) return true;
    if (!(o instanceof Pair)) return false;
    Pair t = (Pair) o;
    return eq(a, t.a) && eq(b, t.b);
  }
  
  public String toString() {
    return "<" + a + ", " + b + ">";
  }
  
  public int compareTo(Pair<A, B> p) {
    if (p == null) return 1;
    int i = ((Comparable<A>) a).compareTo(p.a);
    if (i != 0) return i;
    return ((Comparable<B>) b).compareTo(p.b);
  }
}

static interface IVF1<A> {
  void get(A a);
}

static boolean isAbstract(Class c) {
  return (c.getModifiers() & Modifier.ABSTRACT) != 0;
}

static boolean isAbstract(Method m) {
  return (m.getModifiers() & Modifier.ABSTRACT) != 0;
}
static boolean reflection_isForbiddenMethod(Method m) {
  return m.getDeclaringClass() == Object.class
    && eqOneOf(m.getName(), "finalize", "clone", "registerNatives");
}
static Set<Class> allInterfacesImplementedBy(Class c) {
  if (c == null) return null;
  HashSet<Class> set = new HashSet();
  allInterfacesImplementedBy_find(c, set);
  return set;
}

static void allInterfacesImplementedBy_find(Class c, Set<Class> set) {
  if (c.isInterface() && !set.add(c)) return;
  do {
    for (Class intf : c.getInterfaces())
      allInterfacesImplementedBy_find(intf, set);
  } while ((c = c.getSuperclass()) != null);
}
static Method findMethod(Object o, String method, Object... args) {
  return findMethod_cached(o, method, args);
}

static boolean findMethod_checkArgs(Method m, Object[] args, boolean debug) {
  Class<?>[] types = m.getParameterTypes();
  if (types.length != args.length) {
    if (debug)
      System.out.println("Bad parameter length: " + args.length + " vs " + types.length);
    return false;
  }
  for (int i = 0; i < types.length; i++)
    if (!(args[i] == null || isInstanceX(types[i], args[i]))) {
      if (debug)
        System.out.println("Bad parameter " + i + ": " + args[i] + " vs " + types[i]);
      return false;
    }
  return true;
}
static Method findStaticMethod(Class c, String method, Object... args) {
  Class _c = c;
  while (c != null) {
    for (Method m : c.getDeclaredMethods()) {
      if (!m.getName().equals(method))
        continue;

      if ((m.getModifiers() & Modifier.STATIC) == 0 || !findStaticMethod_checkArgs(m, args))
        continue;

      return m;
    }
    c = c.getSuperclass();
  }
  return null;
}

static boolean findStaticMethod_checkArgs(Method m, Object[] args) {
  Class<?>[] types = m.getParameterTypes();
  if (types.length != args.length)
    return false;
  for (int i = 0; i < types.length; i++)
    if (!(args[i] == null || isInstanceX(types[i], args[i])))
      return false;
  return true;
}

static String unquote(String s) {
  if (s == null) return null;
  if (startsWith(s, '[')) {
    int i = 1;
    while (i < s.length() && s.charAt(i) == '=') ++i;
    if (i < s.length() && s.charAt(i) == '[') {
      String m = s.substring(1, i);
      if (s.endsWith("]" + m + "]"))
        return s.substring(i+1, s.length()-i-1);
    }
  }
  
  if (s.length() > 1) {
    char c = s.charAt(0);
    if (c == '\"' || c == '\'') {
      int l = endsWith(s, c) ? s.length()-1 : s.length();
      StringBuilder sb = new StringBuilder(l-1);
  
      for (int i = 1; i < l; i++) {
        char ch = s.charAt(i);
        if (ch == '\\') {
          char nextChar = (i == l - 1) ? '\\' : s.charAt(i + 1);
          // Octal escape?
          if (nextChar >= '0' && nextChar <= '7') {
              String code = "" + nextChar;
              i++;
              if ((i < l - 1) && s.charAt(i + 1) >= '0'
                      && s.charAt(i + 1) <= '7') {
                  code += s.charAt(i + 1);
                  i++;
                  if ((i < l - 1) && s.charAt(i + 1) >= '0'
                          && s.charAt(i + 1) <= '7') {
                      code += s.charAt(i + 1);
                      i++;
                  }
              }
              sb.append((char) Integer.parseInt(code, 8));
              continue;
          }
          switch (nextChar) {
          case '\"': ch = '\"'; break;
          case '\\': ch = '\\'; break;
          case 'b': ch = '\b'; break;
          case 'f': ch = '\f'; break;
          case 'n': ch = '\n'; break;
          case 'r': ch = '\r'; break;
          case 't': ch = '\t'; break;
          case '\'': ch = '\''; break;
          // Hex Unicode: u????
          case 'u':
              if (i >= l - 5) {
                  ch = 'u';
                  break;
              }
              int code = Integer.parseInt(
                      "" + s.charAt(i + 2) + s.charAt(i + 3)
                         + s.charAt(i + 4) + s.charAt(i + 5), 16);
              sb.append(Character.toChars(code));
              i += 5;
              continue;
          default:
            ch = nextChar; // added by Stefan
          }
          i++;
        }
        sb.append(ch);
      }
      return sb.toString();
    }
  }
    
  return s; // not quoted - return original
}
static List<String> quoteAll(Collection<String> l) {
  List<String> x = new ArrayList();
  for (String s : l)
    x.add(quote(s));
  return x;
}
static int _hashCode(Object a) {
  return a == null ? 0 : a.hashCode();
}
static <A> ArrayList<A> toList(A[] a) { return asList(a); }
static ArrayList<Integer> toList(int[] a) { return asList(a); }
static <A> ArrayList<A> toList(Set<A> s) { return asList(s); }
static <A> ArrayList<A> toList(Iterable<A> s) { return asList(s); }
static boolean arraysEqual(Object[] a, Object[] b) {
  if (a.length != b.length) return false;
  for (int i = 0; i < a.length; i++)
    if (neq(a[i], b[i])) return false;
  return true;
}
static boolean nempty(Collection c) {
  return !empty(c);
}

static boolean nempty(CharSequence s) {
  return !empty(s);
}

static boolean nempty(Object[] o) { return !empty(o); }
static boolean nempty(byte[] o) { return !empty(o); }
static boolean nempty(int[] o) { return !empty(o); }

static boolean nempty(Map m) {
  return !empty(m);
}

static boolean nempty(Iterator i) {
  return i != null && i.hasNext();
}

static boolean nempty(Object o) { return !empty(o); }






static int hashCodeFor(Object a) {
  return a == null ? 0 : a.hashCode();
}


static Method findMethod_cached(Object o, String method, Object... args) { try {
  if (o == null) return null;
  if (o instanceof Class) {
    _MethodCache cache = callOpt_getCache(((Class) o));
    List<Method> methods = cache.cache.get(method);
    if (methods != null) for (Method m : methods)
      if (isStaticMethod(m) && findMethod_checkArgs(m, args, false))
        return m;
    return null;
  } else {
    _MethodCache cache = callOpt_getCache(o.getClass());
    List<Method> methods = cache.cache.get(method);
    if (methods != null) for (Method m : methods)
      if (findMethod_checkArgs(m, args, false))
        return m;
    return null;
  }
} catch (Exception __e) { throw rethrow(__e); } }

static boolean endsWith(String a, String b) {
  return a != null && a.endsWith(b);
}

static boolean endsWith(String a, char c) {
  return nempty(a) && lastChar(a) == c;
}


  static boolean endsWith(String a, String b, Matches m) {
    if (!endsWith(a, b)) return false;
    m.m = new String[] {dropLast(l(b), a)};
    return true;
  }


static String quote(Object o) {
  if (o == null) return "null";
  return quote(str(o));
}

static String quote(String s) {
  if (s == null) return "null";
  StringBuilder out = new StringBuilder((int) (l(s)*1.5+2));
  quote_impl(s, out);
  return out.toString();
}
  
static void quote_impl(String s, StringBuilder out) {
  out.append('"');
  int l = s.length();
  for (int i = 0; i < l; i++) {
    char c = s.charAt(i);
    if (c == '\\' || c == '"')
      out.append('\\').append(c);
    else if (c == '\r')
      out.append("\\r");
    else if (c == '\n')
      out.append("\\n");
    else if (c == '\t')
      out.append("\\t");
    else if (c == '\0')
      out.append("\\0");
    else
      out.append(c);
  }
  out.append('"');
}


static char lastChar(String s) {
  return empty(s) ? '\0' : s.charAt(l(s)-1);
}
static <A> A[] dropLast(A[] a) { return dropLast(a, 1); }
static <A> A[] dropLast(A[] a, int n) {
  if (a == null) return null;
  n = Math.min(n, a.length);
  A[] b = arrayOfSameType(a, a.length-n);
  System.arraycopy(a, 0, b, 0, b.length);
  return b;
}

static <A> List<A> dropLast(List<A> l) {
  return subList(l, 0, l(l)-1);
}

static <A> List<A> dropLast(int n, List<A> l) {
  return subList(l, 0, l(l)-n);
}

static <A> List<A> dropLast(Iterable<A> l) {
  return dropLast(asList(l));
}

static String dropLast(String s) {
  return substring(s, 0, l(s)-1);
}

static String dropLast(String s, int n) {
  return substring(s, 0, l(s)-n);
}

static String dropLast(int n, String s) {
  return dropLast(s, n);
}



static <A> A[] arrayOfSameType(A[] a, int n) {
  return newObjectArrayOfSameType(a, n);
}
static <A> List<A> subList(List<A> l, int startIndex) {
  return subList(l, startIndex, l(l));
}

static <A> List<A> subList(int startIndex, int endIndex, List<A> l) {
  return subList(l, startIndex, endIndex);
}

static <A> List<A> subList(List<A> l, int startIndex, int endIndex) {
  if (l == null) return null;
  int n = l(l);
  startIndex = Math.max(0, startIndex);
  endIndex = Math.min(n, endIndex);
  if (startIndex >= endIndex) return ll();
  if (startIndex == 0 && endIndex == n) return l;
  return l.subList(startIndex, endIndex);
}




static <A> A[] newObjectArrayOfSameType(A[] a, int n) {
  return (A[]) Array.newInstance(a.getClass().getComponentType(), n);
}

}