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 class ArrayTreeSet<A> {
  A[] array;
  
  ArrayTreeSet() {}
  ArrayTreeSet(List<A> l) {
    array = (A[]) new Object[roundUpToPowerOfTwo(l(l))];
    l = sorted(l);
    fill(l, 0, l(array), 0);
  }
  
  void fill(List<A> l, int lIdx1, int lIdx2, int aIdx) {
    if (lIdx2 <= lIdx1) return;
    int middle = (lIdx1+lIdx2)/2;
    array[aIdx] = get(l, middle);
    fill(l, lIdx1, middle, aIdx*2+1);
    fill(l, middle+1, lIdx2, aIdx*2+2);
  }
  
  boolean contains(A a) {
    int i = 0;
    while (i < l(array)) {
      int x = array[i] == null ? -1 : cmp(a, array[i]);
      if (x == 0) return true;
      i = i*2+(x > 0 ? 2 : 1);
    }
    return false;
  }
}

public static void main(final String[] args) throws Exception {
  List<Integer> l = new ArrayList();
  for (int n = 0; n <= 64; n++) {
    if (n != 0) l.add(n*10);
    print("n=" + n); assertEquals(n, l(l));
    ArrayTreeSet tree = new ArrayTreeSet(shuffledList(l));
    printStruct(tree);
    for (int i : l) {
      assertTrue(str(i), tree.contains(i));
      assertFalse(tree.contains(i-1));
      assertFalse(tree.contains(i+1));
    }
  }
  print("OK");
}
static <A> A printStruct(String prefix, A a) {
  printStructure(prefix, a);
  return a;
}

static <A> A printStruct(A a) {
  printStructure(a);
  return a;
}

static int cmp(Number a, Number b) {
  return a == null ? b == null ? 0 : -1 : cmp(a.doubleValue(), b.doubleValue());
}

static int cmp(double a, double b) {
  return a < b ? -1 : a == b ? 0 : 1;
}

static int cmp(String a, String b) {
  return a == null ? b == null ? 0 : -1 : a.compareTo(b);
}

static int cmp(Object a, Object b) {
  if (a == null) return b == null ? 0 : -1;
  if (b == null) return 1;
  return ((Comparable) a).compareTo(b);
}
static void assertFalse(Object o) {
  assertEquals(false, o);
}
  
static boolean assertFalse(boolean b) {
  if (b) throw fail("oops");
  return b;
}

static boolean assertFalse(String msg, boolean b) {
  if (b) throw fail(msg);
  return b;
}

static Map<Thread, Boolean> _registerThread_threads = Collections.synchronizedMap(new WeakHashMap());

static Thread _registerThread(Thread t) {
  _registerThread_threads.put(t, true);
  return t;
}

static void _registerThread() { _registerThread(Thread.currentThread()); }
static <A> A assertEquals(Object x, A y) {
  return assertEquals(null, x, y);
}

static <A> A assertEquals(String msg, Object x, A y) {
  if (!(x == null ? y == null : x.equals(y)))
    throw fail((msg != null ? msg + ": " : "") + y + " != " + x);
  return y;
}
static <A> List<A> shuffledList(List<A> l) {
  return shuffled(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(int[] a) { return a == null ? 0 : a.length; }
static int l(float[] 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(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 instanceof String ? l((String) o)
    : o instanceof Map ? l((Map) o)
    : l((Collection) o); // incomplete
}




static void fill(RGBImage img, String col) {
  RGB rgb = new RGB(col);
  int w = img.getWidth(), h = img.getHeight();
  for (int y = 0; y < h; y++)
    for (int x = 0; x < w; x++)
      img.setPixel(x, y, rgb);
}

static String str(Object o) {
  return o == null ? "null" : o.toString();
}

static String str(char[] c) {
  return new String(c);
}
static <A> List<A> sorted(Collection<A> c, final Object comparator) {
  List<A> l = cloneList(c);
  sort(l, makeComparator(comparator));
  return l;
}

static <A> List<A> sorted(Collection<A> c) {
  List<A> l = cloneList(c);
  sort(l);
  return l;
}
static boolean contains(Collection c, Object o) {
  return c != null && c.contains(o);
}

static boolean contains(Object[] x, Object o) {
  if (x != null)
    for (Object a : x)
      if (eq(a, o))
        return true;
  return false;
}

static boolean contains(String s, char c) {
  return s != null && s.indexOf(c) >= 0;
}

static boolean contains(String s, String b) {
  return s != null && s.indexOf(b) >= 0;
}
static volatile StringBuffer local_log = new StringBuffer(); // not redirected
static volatile StringBuffer 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 int print_maxLineLength = 0; // 0 = unset

static boolean print_silent; // total mute if set

static Object print_byThread_lock = new Object();
static volatile ThreadLocal<F1<String, Boolean>> print_byThread; // special handling by thread

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

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

static void print_noNewLine(String s) {
  if (print_byThread != null) {
    F1<String, Boolean> f = print_byThread.get();
    if (f != null)
      if (isFalse(f.get(s))) return;
  }

  print_raw(s);
}

static void print_raw(String s) {
  s = fixNewLines(s);
  // TODO if (print_maxLineLength != 0)
  StringBuffer loc = local_log;
  StringBuffer 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(long l) {
  print(String.valueOf(l));
}

static void print(char c) {
  print(String.valueOf(c));
}

static void print_append(StringBuffer buf, String s, int max) {
  synchronized(buf) {
    buf.append(s);
    max /= 2;
    if (buf.length() > max) 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);
    }
  }
}
static RuntimeException asRuntimeException(Throwable t) {
  return t instanceof RuntimeException ? (RuntimeException) t : new RuntimeException(t);
}
static void assertTrue(Object o) {
  assertEquals(true, 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 int roundUpToPowerOfTwo(int v) {
  v--;
  v |= v >> 1;
  v |= v >> 2;
  v |= v >> 4;
  v |= v >> 8;
  v |= v >> 16;
  return v+1;
}
// 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 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) {
      f.setAccessible(true);
      return f.get(o);
    }
      
    
      if (o instanceof DynamicObject)
        return ((DynamicObject) o).fieldValues.get(field);
    
  } catch (Exception e) {
    throw asRuntimeException(e);
  }
  throw new RuntimeException("Field '" + field + "' not found in " + o.getClass().getName());
}

static Object get_raw(Object o, String field) {
  try {
    Field f = get_findField(o.getClass(), field);
    f.setAccessible(true);
    return f.get(o);
  } catch (Exception e) {
    throw new RuntimeException(e);
  }
}

static Object get(Class c, String field) {
  try {
    Field f = get_findStaticField(c, field);
    f.setAccessible(true);
    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 String fixNewLines(String s) {
  return s.replace("\r\n", "\n").replace("\r", "\n");
}
static volatile boolean ping_pauseAll;
static int ping_sleep = 100; // poll pauseAll flag every 100
static volatile boolean ping_anyActions;
static Map<Thread, Object> ping_actions = (Map) synchroMap(newWeakHashMap());

// always returns true
static boolean ping() {
  if (ping_pauseAll || ping_anyActions) ping_impl();
  return true;
}

// returns true when it slept
static boolean ping_impl() { try {
  if (ping_pauseAll && !isAWTThread()) {
    do
      Thread.sleep(ping_sleep);
    while (ping_pauseAll);
    return true;
  }
  
  if (ping_anyActions) {
    Object action;
    synchronized(ping_actions) {
      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 void printStructure(String prefix, Object o) {
  if (endsWithLetter(prefix)) prefix += ": ";
  print(prefix + structureForUser(o));
}

static void printStructure(Object o) {
  print(structureForUser(o));
}

static <A> List<A> shuffled(List<A> l) {
  l = cloneList(l);
  Collections.shuffle(l);
  return l;
}
static <A> List<A> cloneList(Collection<A> l) {
  if (l == null) return new ArrayList();
  // assume collection's mutex is equal to collection, which will be true unless you explicitly pass a mutex to synchronizedList() which no one ever does.
  synchronized(l) {
    return new ArrayList<A>(l);
  }
}
static boolean isFalse(Object o) {
  return eq(false, o);
}
static <T> void sort(T[] a, Comparator<? super T> c) {
  Arrays.sort(a, c);
}

static <T> void sort(T[] a) {
  Arrays.sort(a);
}

static <T> void sort(List<T> a, Comparator<? super T> c) {
  Collections.sort(a, c);
}

static void sort(List a) {
  Collections.sort(a);
}
static Comparator makeComparator(final Object f) {
  return new Comparator() {
    public int compare(Object a, Object b) {
      return (int) callF(f, a, b);
    }
  };
}

static boolean eq(Object a, Object b) {
  return a == null ? b == null : a == b || a.equals(b);
}
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 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 Map synchroMap() {
  return synchroHashMap();
}

static <A, B> Map<A, B> synchroMap(Map<A, B> map) {
  return Collections.synchronizedMap(map);
}
static WeakHashMap<Class, ArrayList<Method>> callF_cache = new WeakHashMap();

static <A> A callF(F0<A> f) {
  return f == null ? null : f.get();
}

static Object callF(Object f, Object... args) { try {
  if (f instanceof String)
    return callMC((String) f, args);
  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 methods.get(0).invoke(f, args);
  for (int i = 0; i < n; i++) {
    Method m = methods.get(i);
    if (call_checkArgs(m, args, false))
      return m.invoke(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")) {
        m.setAccessible(true);
        l.add(m);
      }
    if (!l.isEmpty()) break;
    _c = _c.getSuperclass();
  } while (_c != null);
  callF_cache.put(c, l);
  return l;
}
static <A, B> Map<A, B> newWeakHashMap() {
  return _registerWeakMap(synchroMap(new WeakHashMap()));
}
static String structureForUser(Object o) {
  return beautifyStructure(struct_noStringSharing(o));
}
// 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 boolean endsWithLetter(String s) {
  return nempty(s) && isLetter(last(s));
}
static RuntimeException rethrow(Throwable e) {
  throw asRuntimeException(e);
}
static Thread currentThread() {
  return Thread.currentThread();
}


static Boolean isHeadless_cache;

static boolean isHeadless() {
  if (isHeadless_cache != null) return isHeadless_cache;
  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 String struct_noStringSharing(Object o) {
  structure_Data d = new structure_Data();
  d.noStringSharing = true;
  return structure(o, d);
}
static final 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;
  synchronized(callMC_cache) {
    me = method == callMC_key ? callMC_value : null;
  }
  if (me != null) return callMC_value.invoke(null, args);

  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;
    }
    return me.invoke(null, args);
  }
  for (int i = 0; i < n; i++) {
    me = m.get(i);
    if (call_checkArgs(me, args, false))
      return me.invoke(null, args);
  }
  throw fail("No method called " + method + " with matching arguments 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) {
          m.setAccessible(true);
          multiMapPut(callMC_cache, m.getName(), m);
        }
      c = c.getSuperclass();
    }
  }
}
static <A> A last(List<A> l) {
  return empty(l) ? null : l.get(l.size()-1);
}

static char last(String s) {
  return empty(s) ? '#' : s.charAt(l(s)-1);
}

static int last(int[] a) {
  return l(a) != 0 ? a[l(a)-1] : 0;
}
static Object call(Object o) {
  return callFunction(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) {
  try {
    if (o instanceof Class) {
      Method m = call_findStaticMethod((Class) o, method, args, false);
      m.setAccessible(true);
      return m.invoke(null, args);
    } else {
      Method m = call_findMethod(o, method, args, false);
      m.setAccessible(true);
      return m.invoke(o, args);
    }
  } catch (Exception e) {
    throw e instanceof RuntimeException ? (RuntimeException) e : new RuntimeException(e);
  }
}

static Method call_findStaticMethod(Class c, String method, Object[] args, boolean debug) {
  Class _c = c;
  while (c != null) {
    for (Method m : c.getDeclaredMethods()) {
      if (debug)
        System.out.println("Checking method " + m.getName() + " with " + m.getParameterTypes().length + " parameters");;
      if (!m.getName().equals(method)) {
        if (debug) System.out.println("Method name mismatch: " + method);
        continue;
      }

      if ((m.getModifiers() & java.lang.reflect.Modifier.STATIC) == 0 || !call_checkArgs(m, args, debug))
        continue;

      return m;
    }
    c = c.getSuperclass();
  }
  throw new RuntimeException("Method '" + method + "' (static) with " + args.length + " parameter(s) not found in " + _c.getName());
}

static Method call_findMethod(Object o, String method, Object[] args, boolean debug) {
  Class c = o.getClass();
  while (c != null) {
    for (Method m : c.getDeclaredMethods()) {
      if (debug)
        System.out.println("Checking method " + m.getName() + " with " + m.getParameterTypes().length + " parameters");;
      if (m.getName().equals(method) && call_checkArgs(m, args, debug))
        return m;
    }
    c = c.getSuperclass();
  }
  throw new RuntimeException("Method '" + method + "' (non-static) with " + args.length + " parameter(s) not found in " + o.getClass().getName());
}

private static boolean call_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 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 String getClassName(Object o) {
  return o == null ? "null" : o instanceof Class ? ((Class) o).getName() : o.getClass().getName();
}
static String beautifyStructure(String s) {
  return structure_addTokenMarkers(s);
}
static boolean isLetter(char c) {
  return Character.isLetter(c);
}
static boolean nempty(Collection c) {
  return !isEmpty(c);
}

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

static boolean nempty(Object[] o) {
  return !isEmpty(o);
}

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

static boolean nempty(Iterator i) {
  return i != null && i.hasNext();
}
static Map synchroHashMap() {
  return Collections.synchronizedMap(new HashMap());
}

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 Object callFunction(Object f, Object... args) {
  return callF(f, args);
}
static boolean empty(Collection c) { return c == null || c.isEmpty(); }
static boolean empty(String 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);
  throw fail("unknown type for 'empty': " + getType(o));
}

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 Class javax() {
  return getJavaX();
}
static Class mc() {
  return main.class;
}
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 String structure_addTokenMarkers(String s) {
  List<String> tok = javaTok(s);
  
  // find references
  
  TreeSet<Integer> refs = new TreeSet();
  for (int i = 1; i < l(tok); i += 2) {
    String t = tok.get(i);
    if (t.startsWith("t") && isInteger(t.substring(1)))
      refs.add(parseInt(t.substring(1)));
  }
  
  if (empty(refs)) return s;
  
  // add markers
  for (int i : refs) {
    int idx = i*2+1;
    String t = "";
    if (endsWithLetterOrDigit(tok.get(idx-1))) t = " ";
    tok.set(idx, t + "m" + i + " " + tok.get(idx));
  }
  
  return join(tok);
}
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);
}
// extended over Class.isInstance() to handle primitive types
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 void printException(Throwable e) {
  printStackTrace(e);
}
static <A> List<A> synchroList() {
  return Collections.synchronizedList(new ArrayList<A>());
}

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

static boolean isEmpty(Collection c) {
  return c == null || c.isEmpty();
}

static boolean isEmpty(CharSequence s) {
  return s == null || s.length() == 0;
}

static boolean isEmpty(Object[] a) {
  return a == null || a.length == 0;
}

static boolean isEmpty(Map map) {
  return map == null || map.isEmpty();
}
static boolean structure_showTiming, structure_checkTokenCount;

static String structure(Object o) {
  return structure(o, new structure_Data());
}

static String structure(Object o, structure_Data d) {
  StringWriter sw = new StringWriter();
  d.out = new PrintWriter(sw);
  structure_go(o, d);
  String s = str(sw);
  if (structure_checkTokenCount) {
    print("token count=" + d.n);
    assertEquals("token count", l(javaTokC(s)), d.n);
  }
  return s;
}

static void structure_go(Object o, structure_Data d) {
  structure_1(o, d);
  while (nempty(d.stack))
    popLast(d.stack).run();
}

static void structureToPrintWriter(Object o, PrintWriter out) {
  structure_Data d = new structure_Data();
  d.out = out;
  structure_go(o, d);
}

// leave to false, unless unstructure() breaks
static boolean structure_allowShortening = false;

static class structure_Data {
  PrintWriter out;
  int stringSizeLimit;
  int shareStringsLongerThan = 20;
  boolean noStringSharing;

  IdentityHashMap<Object,Integer> seen = new IdentityHashMap();
  //new BitSet refd;
  HashMap<String,Integer> strings = new HashMap();
  HashSet<String> concepts = new HashSet();
  HashMap<Class, List<Field>> fieldsByClass = new HashMap();
  int n; // token count
  List<Runnable> stack = new ArrayList();
  
  // append single token
  structure_Data append(String token) { out.print(token); ++n; return this; }
  structure_Data append(int i) { out.print(i); ++n; return this; }
  
  // append multiple tokens
  structure_Data append(String token, int tokCount) { out.print(token); n += tokCount; return this; }
  
  // extend last token
  structure_Data app(String token) { out.print(token); return this; }
  structure_Data app(int i) { out.print(i); return this; }
}

static void structure_1(final Object o, final structure_Data d) {
  if (o == null) { d.append("null"); return; }
  
  Class c = o.getClass();
  boolean concept = false;
  
  List<Field> lFields = d.fieldsByClass.get(c);
  
  if (lFields == null) {
    // these are never back-referenced (for readability)
    
    if (o instanceof Number) {
      PrintWriter out = d.out;
if (o instanceof Integer) { int i = ((Integer) o).intValue(); out.print(i); d.n += i < 0 ? 2 : 1; return; }
      if (o instanceof Long) { long l = ((Long) o).longValue(); out.print(l); out.print("L"); d.n += l < 0 ? 2 : 1; return; }
      if (o instanceof Float) { d.append("fl ", 2); quoteToPrintWriter(str(o), out); return; }
      if (o instanceof Double) { d.append("d(", 3); quoteToPrintWriter(str(o), out); d.append(")"); return; }
      if (o instanceof BigInteger) { out.print("bigint("); out.print(o); out.print(")"); d.n += ((BigInteger) o).signum() < 0 ? 5 : 4; return; }
    }
  
    if (o instanceof Boolean) {
      d.append(((Boolean) o).booleanValue() ? "t" : "f"); return;
    }
      
    if (o instanceof Character) {
      d.append(quoteCharacter((Character) o)); return;
    }
      
    if (o instanceof File) {
      d.append("File ").append(quote(((File) o).getPath())); return;
    }
      
    // referencable objects follow
    
    Integer ref = d.seen.get(o);
    if (o instanceof String && ref == null) ref = d.strings.get((String) o);
    if (ref != null) { /*d.refd.set(ref);*/ d.append("t").app(ref); return; }

    if (!(o instanceof String))
      d.seen.put(o, d.n); // record token number
    else {
      String s = d.stringSizeLimit != 0 ? shorten((String) o, d.stringSizeLimit) : (String) o;
      if (!d.noStringSharing) {
        if (d.shareStringsLongerThan == Integer.MAX_VALUE)
          d.seen.put(o, d.n);
        if (l(s) >= d.shareStringsLongerThan)
          d.strings.put(s, d.n);
      }
      quoteToPrintWriter(s, d.out); d.n++; return;
    }
      
    if (o instanceof HashSet) {
      d.append("hashset ");
      structure_1(new ArrayList((Set) o), d);
      return;
    }
  
    if (o instanceof TreeSet) {
      d.append("treeset ");
      structure_1(new ArrayList((Set) o), d);
      return;
    }
    
    String name = c.getName();
    if (o instanceof Collection
      && !startsWith(name, "main$")
      /* && neq(name, "main$Concept$RefL") */) {
      d.append("[");
      final int l = d.n;
      final Iterator it = ((Collection) o).iterator();
      d.stack.add(new Runnable() { public void run() { try { 
        if (!it.hasNext())
          d.append("]");
        else {
          d.stack.add(this);
          if (d.n != l) d.append(", ");
          structure_1(it.next(), d);
        }
      
} catch (Exception __e) { throw rethrow(__e); } }  public String toString() { return "if (!it.hasNext())\r\n          d.append(\"]\");\r\n        else {\r\n          d.stack...."; }});
      return;
    }
    
    if (o instanceof Map && !startsWith(name, "main$")) {
      if (o instanceof LinkedHashMap) d.append("lhm");
      else if (o instanceof HashMap) d.append("hm");
      d.append("{");
      final int l = d.n;
      final Iterator it = ((Map) o).entrySet().iterator();
      
      d.stack.add(new Runnable() {
        boolean v;
        Map.Entry e;
        
        public void run() {
          if (v) {
            d.append("=");
            v = false;
            d.stack.add(this);
            structure_1(e.getValue(), d);
          } else {
            if (!it.hasNext())
              d.append("}");
            else {
              e = (Map.Entry) it.next();
              v = true;
              d.stack.add(this);
              if (d.n != l) d.append(", ");
              structure_1(e.getKey(), d);
            }
          }
        }
      });
      return;
    }
    
    if (c.isArray()) {
      if (o instanceof byte[]) {
        d.append("ba ").append(quote(bytesToHex((byte[]) o))); return;
      }
  
      final int n = Array.getLength(o);
  
      if (o instanceof boolean[]) {
        String hex = boolArrayToHex((boolean[]) o);
        int i = l(hex);
        while (i > 0 && hex.charAt(i-1) == '0' && hex.charAt(i-2) == '0') i -= 2;
        d.append("boolarray ").append(n).app(" ").append(quote(substring(hex, 0, i))); return;
      }
      
      String atype = "array", sep = ", ";
  
      if (o instanceof int[]) {
        //ret "intarray " + quote(intArrayToHex((int[]) o));
        atype = "intarray";
        sep = " ";
      }
      
      d.append(atype).append("{");
      d.stack.add(new Runnable() {
        int i;
        public void run() {
          if (i >= n)
            d.append("}");
          else {
            d.stack.add(this);
            if (i > 0) d.append(", ");
            structure_1(Array.get(o, i++), d);
          }
        }
      });
      return;
    }
  
    if (o instanceof Class) {
      d.append("class(", 2).append(quote(((Class) o).getName())).append(")"); return;
    }
      
    if (o instanceof Throwable) {
      d.append("exception(", 2).append(quote(((Throwable) o).getMessage())).append(")"); return;
    }
      
    if (o instanceof BitSet) {
      BitSet bs = (BitSet) o;
      d.append("bitset{", 2);
      int l = d.n;
      for (int i = bs.nextSetBit(0); i >= 0; i = bs.nextSetBit(i+1)) {
        if (d.n != l) d.append(", ");
        d.append(i);
      }
      d.append("}"); return;
    }
      
    // Need more cases? This should cover all library classes...
    if (name.startsWith("java.") || name.startsWith("javax.")) {
      d.append("j ").append(quote(str(o))); return; // Hm. this is not unstructure-able
    }
    
    
      
    /*if (name.equals("main$Lisp")) {
      fail("lisp not supported right now");
    }*/
    
    String dynName = shortDynamicClassName(o);
    if (concept && !d.concepts.contains(dynName)) {
      d.concepts.add(dynName);
      d.append("c ");
    }
    
    // serialize an object with fields.
    // first, collect all fields and values in fv.
    
    TreeSet<Field> fields = new TreeSet<Field>(new Comparator<Field>() {
      public int compare(Field a, Field b) {
        return stdcompare(a.getName(), b.getName());
      }
    });
    
    Class cc = c;
    while (cc != Object.class) {
      for (Field field : getDeclaredFields_cached(cc)) {
        if ((field.getModifiers() & (java.lang.reflect.Modifier.STATIC | java.lang.reflect.Modifier.TRANSIENT)) != 0)
          continue;
        String fieldName = field.getName();
        
        fields.add(field);
        
        // put special cases here...
      }
        
      cc = cc.getSuperclass();
    }
    
    lFields = asList(fields);
    
    // Render this$1 first because unstructure needs it for constructor call.
    
    for (int i = 0; i < l(lFields); i++) {
      Field f = lFields.get(i);
      if (f.getName().equals("this$1")) {
        lFields.remove(i);
        lFields.add(0, f);
        break;
      }
    }
  
    
    d.fieldsByClass.put(c, lFields);
  } // << if (lFields == null)
  else { // ref handling for lFields != null
    Integer ref = d.seen.get(o);
    if (ref != null) { /*d.refd.set(ref);*/ d.append("t").app(ref); return; }
    d.seen.put(o, d.n); // record token number
  }

  LinkedHashMap<String,Object> fv = new LinkedHashMap();
  for (Field f : lFields) {
    Object value;
    try {
      value = f.get(o);
    } catch (Exception e) {
      value = "?";
    }
      
    if (value != null)
      fv.put(f.getName(), value);
    
  }
  
  String name = c.getName();
  String shortName = dropPrefix("main$", name);
    
  // Now we have fields & values. Process fieldValues if it's a DynamicObject.
  
  // omit field "className" if equal to class's name
  if (concept && eq(fv.get("className"), shortName))
    fv.remove("className");
          
  if (o instanceof DynamicObject) {
    fv.putAll((Map) fv.get("fieldValues"));
    fv.remove("fieldValues");
    shortName = shortDynamicClassName(o);
    fv.remove("className");
  }
  
  String singleField = fv.size() == 1 ? first(fv.keySet()) : null;
  
  d.append(shortName);
  
  
  final int l = d.n;
  final Iterator it = fv.entrySet().iterator();
  
  d.stack.add(new Runnable() { public void run() { try { 
    if (!it.hasNext()) {
      if (d.n != l)
        d.append(")");
    } else {
      Map.Entry e = (Map.Entry) it.next();
      d.append(d.n == l ? "(" : ", ");
      d.append((String) e.getKey()).append("=");
      d.stack.add(this);
      structure_1(e.getValue(), d);
    }
  
} catch (Exception __e) { throw rethrow(__e); } }  public String toString() { return "if (!it.hasNext()) {\r\n      if (d.n != l)\r\n        d.append(\")\");\r\n    } else {\r..."; }});
}



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) {
  ArrayList<Integer> l = new ArrayList();
  for (int 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;
}
  public static String bytesToHex(byte[] bytes) {
    return bytesToHex(bytes, 0, bytes.length);
  }

  public static String bytesToHex(byte[] bytes, int ofs, int len) {
    StringBuilder stringBuilder = new StringBuilder(len*2);
    for (int i = 0; i < len; i++) {
      String s = "0" + Integer.toHexString(bytes[ofs+i]);
      stringBuilder.append(s.substring(s.length()-2, s.length()));
    }
    return stringBuilder.toString();
  }

static boolean isInteger(String s) {
  if (s == null) return false;
  int n = l(s);
  if (n == 0) return false;
  int i = 0;
  if (s.charAt(0) == '-')
    if (++i >= n) return false;
  while (i < n) {
    char c = s.charAt(i);
    if (c < '0' || c > '9') return false;
    ++i;
  }
  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
      out.append(c);
  }
  out.append('"');
}
static int shorten_default = 100;

static String shorten(String s) { return shorten(s, shorten_default); }

static String shorten(String s, int max) {
  if (s == null) return "";
  if (max < 0) return s;
  return s.length() <= max ? s : s.substring(0, Math.min(s.length(), max)) + "...";
}

static String shorten(int max, String s) { return shorten(s, max); }
static String quoteCharacter(char c) {
  if (c == '\'') return "'\\''";
  if (c == '\\') return "'\\\\'";
  if (c == '\r') return "'\\r'";
  if (c == '\n') return "'\\n'";
  if (c == '\t') return "'\\t'";
  return "'" + c + "'";
}

public static String join(String glue, Iterable<String> strings) {
  if (strings == null) return "";
  StringBuilder buf = new StringBuilder();
  Iterator<String> 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 String join(Iterable<String> strings) {
  return join("", strings);
}

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

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


static void quoteToPrintWriter(String s, PrintWriter out) {
  if (s == null) { out.print("null"); return; }
  out.print('"');
  int l = s.length();
  for (int i = 0; i < l; i++) {
    char c = s.charAt(i);
    if (c == '\\' || c == '"') {
      out.print('\\'); out.print(c);
    } else if (c == '\r')
      out.print("\\r");
    else if (c == '\n')
      out.print("\\n");
    else
      out.print(c);
  }
  out.print('"');
}
static String shortDynamicClassName(Object o) {
 if (o instanceof DynamicObject && ((DynamicObject) o).className != null)
    return ((DynamicObject) o).className;
  return shortClassName(o);
}
static String dropPrefix(String prefix, String s) {
  return s == null ? null : s.startsWith(prefix) ? s.substring(l(prefix)) : s;
}
static Throwable printStackTrace(Throwable 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(S indent, Throwable e) {
  if (endsWithLetter(indent)) indent += " ";
  printIndent(indent, getStackTrace(e));
}*/
static String getType(Object o) {
  return getClassName(o);
}
// replacement for class JavaTok
// maybe incomplete, might want to add floating point numbers
// todo also: extended multi-line strings

static int javaTok_n, javaTok_elements;
static boolean javaTok_opt;

static List<String> javaTok(String s) {
  return javaTok(s, null);
}

static List<String> javaTok(String s, List<String> existing) {
  ++javaTok_n;
  int nExisting = javaTok_opt && existing != null ? existing.size() : 0;
  ArrayList<String> tok = existing != null ? new ArrayList(nExisting) : new ArrayList();
  int l = s.length();
  
  int i = 0, n = 0;
  while (i < l) {
    int j = i;
    char c, d;
    
    // scan for whitespace
    while (j < l) {
      c = s.charAt(j);
      d = j+1 >= l ? '\0' : s.charAt(j+1);
      if (c == ' ' || c == '\t' || c == '\r' || c == '\n')
        ++j;
      else if (c == '/' && d == '*') {
        do ++j; while (j < l && !s.substring(j, Math.min(j+2, l)).equals("*/"));
        j = Math.min(j+2, l);
      } else if (c == '/' && d == '/') {
        do ++j; while (j < l && "\r\n".indexOf(s.charAt(j)) < 0);
      } else
        break;
    }
    
    if (n < nExisting && javaTok_isCopyable(existing.get(n), s, i, j))
      tok.add(existing.get(n));
    else
      tok.add(quickSubstring(s, i, j));
    ++n;
    i = j;
    if (i >= l) break;
    c = s.charAt(i);
    d = i+1 >= l ? '\0' : s.charAt(i+1);

    // scan for non-whitespace
    
    // Special JavaX syntax: 'identifier
    if (c == '\'' && Character.isJavaIdentifierStart(d) && i+2 < l && "'\\".indexOf(s.charAt(i+2)) < 0) {
      j += 2;
      while (j < l && Character.isJavaIdentifierPart(s.charAt(j)))
        ++j;
    } else if (c == '\'' || c == '"') {
      char opener = c;
      ++j;
      while (j < l) {
        if (s.charAt(j) == opener /*|| s.charAt(j) == '\n'*/) { // allow multi-line strings
          ++j;
          break;
        } else if (s.charAt(j) == '\\' && j+1 < l)
          j += 2;
        else
          ++j;
      }
    } else if (Character.isJavaIdentifierStart(c))
      do ++j; while (j < l && (Character.isJavaIdentifierPart(s.charAt(j)) || "'".indexOf(s.charAt(j)) >= 0)); // for stuff like "don't"
    else if (Character.isDigit(c)) {
      do ++j; while (j < l && Character.isDigit(s.charAt(j)));
      if (j < l && s.charAt(j) == 'L') ++j; // Long constants like 1L
    } else if (c == '[' && d == '[') {
      do ++j; while (j+1 < l && !s.substring(j, j+2).equals("]]"));
      j = Math.min(j+2, l);
    } else if (c == '[' && d == '=' && i+2 < l && s.charAt(i+2) == '[') {
      do ++j; while (j+2 < l && !s.substring(j, j+3).equals("]=]"));
      j = Math.min(j+3, l);
    } else
      ++j;
      
    if (n < nExisting && javaTok_isCopyable(existing.get(n), s, i, j))
      tok.add(existing.get(n));
    else
      tok.add(quickSubstring(s, i, j));
    ++n;
    i = j;
  }
  
  if ((tok.size() % 2) == 0) tok.add("");
  javaTok_elements += tok.size();
  return tok;
}

static List<String> javaTok(List<String> tok) {
  return javaTok(join(tok), tok);
}

static boolean javaTok_isCopyable(String t, String s, int i, int j) {
  return t.length() == j-i
    && s.regionMatches(i, t, 0, j-i); // << could be left out, but that's brave
}
static String substring(String s, int x) {
  return substring(s, x, l(s));
}

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


static Class __javax;

static Class getJavaX() {
  return __javax;
}
static List<String> javaTokC(String s) {
  if (s == null) return null;
  int l = s.length();
  ArrayList<String> tok = new ArrayList();
  
  int i = 0;
  while (i < l) {
    int j = i;
    char c, d;
    
    // scan for whitespace
    while (j < l) {
      c = s.charAt(j);
      d = j+1 >= l ? '\0' : s.charAt(j+1);
      if (c == ' ' || c == '\t' || c == '\r' || c == '\n')
        ++j;
      else if (c == '/' && d == '*') {
        do ++j; while (j < l && !s.substring(j, Math.min(j+2, l)).equals("*/"));
        j = Math.min(j+2, l);
      } else if (c == '/' && d == '/') {
        do ++j; while (j < l && "\r\n".indexOf(s.charAt(j)) < 0);
      } else
        break;
    }
    
    i = j;
    if (i >= l) break;
    c = s.charAt(i);
    d = i+1 >= l ? '\0' : s.charAt(i+1);

    // scan for non-whitespace
    if (c == '\'' || c == '"') {
      char opener = c;
      ++j;
      while (j < l) {
        if (s.charAt(j) == opener || s.charAt(j) == '\n') { // end at \n to not propagate unclosed string literal errors
          ++j;
          break;
        } else if (s.charAt(j) == '\\' && j+1 < l)
          j += 2;
        else
          ++j;
      }
    } else if (Character.isJavaIdentifierStart(c))
      do ++j; while (j < l && (Character.isJavaIdentifierPart(s.charAt(j)) || "'".indexOf(s.charAt(j)) >= 0)); // for stuff like "don't"
    else if (Character.isDigit(c)) {
      do ++j; while (j < l && Character.isDigit(s.charAt(j)));
      if (j < l && s.charAt(j) == 'L') ++j; // Long constants like 1L
    } else if (c == '[' && d == '[') {
      do ++j; while (j+1 < l && !s.substring(j, j+2).equals("]]"));
      j = Math.min(j+2, l);
    } else if (c == '[' && d == '=' && i+2 < l && s.charAt(i+2) == '[') {
      do ++j; while (j+2 < l && !s.substring(j, j+3).equals("]=]"));
      j = Math.min(j+3, l);
    } else
      ++j;
      
    tok.add(quickSubstring(s, i, j));
    i = j;
  }
  
  return tok;
}

static int parseInt(String s) {
  return empty(s) ? 0 : Integer.parseInt(s);
}

static int parseInt(char c) {
  return Integer.parseInt(str(c));
}
static HashMap<Class, Field[]> getDeclaredFields_cache = new HashMap();

static Field[] getDeclaredFields_cached(Class c) {
  Field[] fields;
  synchronized(getDeclaredFields_cache) {
    fields = getDeclaredFields_cache.get(c);
    if (fields == null) {
      getDeclaredFields_cache.put(c, fields = c.getDeclaredFields());
      for (Field f : fields)
        f.setAccessible(true);
    }
  }
  return fields;
}
static <A> A popLast(List<A> l) {
  return liftLast(l);
}
static String boolArrayToHex(boolean[] a) {
  return bytesToHex(boolArrayToBytes(a));
}
static boolean endsWithLetterOrDigit(String s) {
  return nempty(s) && isLetterOrDigit(lastCharacter(s));
}
static int stdcompare(Number a, Number b) {
  return cmp(a, b);
}

static int stdcompare(String a, String b) {
  return cmp(a, b);
}

static int stdcompare(long a, long b) {
  return a < b ? -1 : a > b ? 1 : 0;
}

static int stdcompare(Object a, Object b) {
  return cmp(a, b);
}

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

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

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



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




static String getStackTrace(Throwable throwable) {
  lastException(throwable);
  StringWriter writer = new StringWriter();
  throwable.printStackTrace(new PrintWriter(writer));
  return hideCredentials(writer.toString());
}
static boolean neq(Object a, Object b) {
  return !eq(a, b);
}
static byte[] boolArrayToBytes(boolean[] a) {
  byte[] b = new byte[(l(a)+7)/8];
  for (int i = 0; i < l(a); i++)
    if (a[i])
      b[i/8] |= 1 << (i & 7);
  return b;
}
static boolean isLetterOrDigit(char c) {
  return Character.isLetterOrDigit(c);
}
static String quickSubstring(String s, int i, int j) {
  if (i == j) return "";
  return s.substring(i, j);
}
static <A> A liftLast(List<A> l) {
  if (l.isEmpty()) return null;
  int i = l(l)-1;
  A a = l.get(i);
  l.remove(i);
  return a;
}
static String shortClassName(Object o) {
  if (o == null) return null;
  Class c = o instanceof Class ? (Class) o : o.getClass();
  String name = c.getName();
  return shortenClassName(name);
}
static char lastCharacter(String s) {
  return empty(s) ? 0 : s.charAt(l(s)-1);
}


static volatile Throwable lastException_lastException;

static Throwable lastException() {
  return lastException_lastException;
}

static void lastException(Throwable e) {
  lastException_lastException = e;
}
static String shortenClassName(String name) {
  if (name == null) return null;
  int i = lastIndexOf(name, "$");
  if (i < 0) i = lastIndexOf(name, ".");
  return i < 0 ? name : substring(name, i+1);
}
static String hideCredentials(URL url) { return url == null ? null : hideCredentials(str(url)); }

static String hideCredentials(String url) {
  return url.replaceAll("([&?])_pass=[^&\\s\"]*", "$1_pass=<hidden>");
}


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


static abstract class F0<A> {
  abstract A get();
}

static abstract class F1<A, B> {
  abstract B get(A a);
}

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

static class DynamicObject {
  String className; // just the name, without the "main$"
  LinkedHashMap<String,Object> fieldValues = new LinkedHashMap();
  
  DynamicObject() {}
  // className = just the name, without the "main$"
  DynamicObject(String className) {
  this.className = className;}
}

static class RGB {
  public float r, g, b; // can't be final cause persistence
  
  RGB() {}
  
  public RGB(float r, float g, float b) {
    this.r = r;
    this.g = g;
    this.b = b;
  }

  public RGB(double r, double g, double b) {
    this.r = (float) r;
    this.g = (float) g;
    this.b = (float) b;
  }

  public RGB(int rgb) {
    this(new Color(rgb));
  }
  
  public RGB(double brightness) {
    this.r = this.g = this.b = max(0f, min(1f, (float) brightness));
  }

  public RGB(Color color) {
    this.r = color.getRed()/255f;
    this.g = color.getGreen()/255f;
    this.b = color.getBlue()/255f;
  }

  public RGB(String hex) {
    r = Integer.parseInt(hex.substring(0, 2), 16)/255f;
    g = Integer.parseInt(hex.substring(2, 4), 16)/255f;
    b = Integer.parseInt(hex.substring(4, 6), 16)/255f;
  }

  public float getComponent(int i) {
    return i == 0 ? r : i == 1 ? g : b;
  }

  public Color getColor() {
    return new Color(r, g, b);
  }

  public static RGB newSafe(float r, float g, float b) {
    return new RGB(Math.max(0, Math.min(1, r)), Math.max(0, Math.min(1, g)), Math.max(0, Math.min(1, b)));
  }

  int asInt() { return getColor().getRGB() & 0xFFFFFF; }
  int getInt() { return getColor().getRGB() & 0xFFFFFF; }

  public float getBrightness() {
    return (r+g+b)/3.0f;
  }

  public String getHexString() {
    return Integer.toHexString(asInt() | 0xFF000000).substring(2).toUpperCase();
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (!(o instanceof RGB)) return false;

    RGB rgb = (RGB) o;

    if (Float.compare(rgb.b, b) != 0) return false;
    if (Float.compare(rgb.g, g) != 0) return false;
    if (Float.compare(rgb.r, r) != 0) return false;

    return true;
  }

  @Override
  public int hashCode() {
    int result = (r != +0.0f ? Float.floatToIntBits(r) : 0);
    result = 31 * result + (g != +0.0f ? Float.floatToIntBits(g) : 0);
    result = 31 * result + (b != +0.0f ? Float.floatToIntBits(b) : 0);
    return result;
  }

  public boolean isBlack() {
    return r == 0f && g == 0f && b == 0f;
  }

  public boolean isWhite() {
    return r == 1f && g == 1f && b == 1f;
  }

  public String toString() {
    return getHexString();
  }
}

static class RGBImage {
  transient BufferedImage bufferedImage;
  File file;
  int width, height;
  int[] pixels;

  RGBImage() {}

  RGBImage(BufferedImage image) {
    this(image, null);
  }

  RGBImage(BufferedImage image, File file) {
    this.file = file;
    bufferedImage = image;
    width = image.getWidth();
    height = image.getHeight();
    pixels = new int[width*height];
    PixelGrabber pixelGrabber = new PixelGrabber(image, 0, 0, width, height, pixels, 0, width);
    try {
      if (!pixelGrabber.grabPixels())
        throw new RuntimeException("Could not grab pixels");
      cleanPixels(); // set upper byte to 0
    } catch (InterruptedException e) {
      throw new RuntimeException(e);
    }
  }

  /** We assume it's a file name to load from */
  RGBImage(String file) throws IOException {
    this(new File(file));
  }

  RGBImage(Dimension size, Color color) {
    this(size.width, size.height, color);
  }

  RGBImage(Dimension size, RGB color) {
    this(size.width, size.height, color);
  }

  private void cleanPixels() {
    for (int i = 0; i < pixels.length; i++)
      pixels[i] &= 0xFFFFFF;
  }

  RGBImage(int width, int height, int[] pixels) {
    this.width = width;
    this.height = height;
    this.pixels = pixels;
  }

  RGBImage(int w, int h, RGB[] pixels) {
    this.width = w;
    this.height = h;
    this.pixels = asInts(pixels);
  }

  public static int[] asInts(RGB[] pixels) {
    int[] ints = new int[pixels.length];
    for (int i = 0; i < pixels.length; i++)
      ints[i] = pixels[i] == null ? 0 : pixels[i].getColor().getRGB();
    return ints;
  }

  public RGBImage(int w, int h) {
    this(w, h, Color.black);
  }
  
  RGBImage(int w, int h, RGB rgb) {
    this.width = w;
    this.height = h;
    this.pixels = new int[w*h];
    int col = rgb.asInt();
    if (col != 0)
      for (int i = 0; i < pixels.length; i++)
        pixels[i] = col;
  }

  RGBImage(RGBImage image) {
    this(image.width, image.height, copyPixels(image.pixels));
  }

  RGBImage(int width, int height, Color color) {
    this(width, height, new RGB(color));
  }

  RGBImage(File file) throws IOException {
    this(javax.imageio.ImageIO.read(file));
  }

  private static int[] copyPixels(int[] pixels) {
    int[] copy = new int[pixels.length];
    System.arraycopy(pixels, 0, copy, 0, pixels.length);
    return copy;
  }

  public int getIntPixel(int x, int y) {
    if (inRange(x, y))
      return pixels[y * width + x];
    else
      return 0xFFFFFF;
  }

  public static RGB asRGB(int packed) {
    int r = (packed >> 16) & 0xFF;
    int g = (packed >> 8) & 0xFF;
    int b = packed & 0xFF;
    return new RGB(r / 255f, g / 255f, b / 255f);
  }

  public RGB getRGB(int x, int y) {
    if (inRange(x, y))
      return asRGB(pixels[y * width + x]);
    else
      return new RGB(0xFFFFFF);
  }

  /** alias of getRGB - I kept typing getPixel instead of getRGB all the time, so I finally created it */
  RGB getPixel(int x, int y) {
    return getRGB(x, y);
  }
  
  RGB getPixel(Pt p) { return getPixel(p.x, p.y); }

  int getWidth() { return width; }
  int getHeight() { return height; }
  int w() { return width; }
  int h() { return height; }

  /** Attention: cached, i.e. does not change when image itself changes */
  /** @NotNull */
  public BufferedImage getBufferedImage() {
    if (bufferedImage == null) {
      bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
      //bufferedImage.setData(Raster.createRaster(new SampleModel()));
      for (int y = 0; y < height; y++)
        for (int x = 0; x < width; x++)
          bufferedImage.setRGB(x, y, pixels[y*width+x]);
    }
    return bufferedImage;
  }

  RGBImage clip(Rect r) {
    return r == null ? null : clip(r.getRectangle());
  }
  
  RGBImage clip(Rectangle r) {
    r = fixClipRect(r);
    int[] newPixels;
    try {
      newPixels = new int[r.width*r.height];
    } catch (RuntimeException e) {
      System.out.println(r);
      throw e;
    }
    for (int y = 0; y < r.height; y++) {
      System.arraycopy(pixels, (y+r.y)*width+r.x, newPixels, y*r.width, r.width);
    }
    return new RGBImage(r.width, r.height, newPixels);
  }

  private Rectangle fixClipRect(Rectangle r) {
    r = r.intersection(new Rectangle(0, 0, width, height));
    if (r.isEmpty())
      r = new Rectangle(r.x, r.y, 0, 0);
    return r;
  }

  public File getFile() {
    return file;
  }

  /** can now also do GIF (not just JPEG) */
  public static RGBImage load(String fileName) {
    return load(new File(fileName));
  }

  /** can now also do GIF (not just JPEG) */
  public static RGBImage load(File file) {
    try {
      BufferedImage bufferedImage = javax.imageio.ImageIO.read(file);
      return new RGBImage(bufferedImage);
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }

  public int getInt(int x, int y) {
    return pixels[y * width + x];
  }

  public void save(File file) throws IOException {
    String name = file.getName().toLowerCase();
    String type;
    if (name.endsWith(".png")) type = "png";
    else if (name.endsWith(".jpg") || name.endsWith(".jpeg")) type = "jpeg";
    else throw new IOException("Unknown image extension: " + name);
    javax.imageio.ImageIO.write(getBufferedImage(), type, file);
  }

  public static RGBImage dummyImage() {
    return new RGBImage(1, 1, new int[] {0xFFFFFF});
  }

  public int[] getPixels() {
    return pixels;
  }

  public void setPixel(int x, int y, RGB rgb) {
    if (x >= 0 && y >= 0 && x < width && y < height)
      pixels[y*width+x] = rgb.asInt();
  }

  public void setPixel(int x, int y, Color color) {
    setPixel(x, y, new RGB(color));
  }

  public void setPixel(int x, int y, int rgb) {
    if (x >= 0 && y >= 0 && x < width && y < height)
      pixels[y*width+x] = rgb;
  }
  
  void setPixel(Pt p, RGB rgb) { setPixel(p.x, p.y, rgb); }
  void setPixel(Pt p, Color color) { setPixel(p.x, p.y, color); }

  public RGBImage copy() {
    return new RGBImage(this);
  }

  public boolean inRange(int x, int y) {
    return x >= 0 && y >= 0 && x < width && y < height;
  }

  public Dimension getSize() {
    return new Dimension(width, height);
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (o == null || getClass() != o.getClass()) return false;

    RGBImage rgbImage = (RGBImage) o;

    if (height != rgbImage.height) return false;
    if (width != rgbImage.width) return false;
    if (!Arrays.equals(pixels, rgbImage.pixels)) return false;

    return true;
  }

  @Override
  public int hashCode() {
    int result = width;
    result = 31 * result + height;
    result = 31 * result + Arrays.hashCode(pixels);
    return result;
  }

  public String getHex(int x, int y) {
    return getPixel(x, y).getHexString();
  }

  public RGBImage clip(int x, int y, int width, int height) {
    return clip(new Rectangle(x, y, width, height));
  }

  public RGBImage clipLine(int y) {
    return clip(0, y, width, 1);
  }

  public int numPixels() {
    return width*height;
  }
}



static int min(int a, int b) {
  return Math.min(a, b);
}

static long min(long a, long b) {
  return Math.min(a, b);
}

static float min(float a, float b) { return Math.min(a, b); }
static float min(float a, float b, float c) { return min(min(a, b), c); }

static double min(double a, double b) {
  return Math.min(a, b);
}

static double min(double[] c) {
  double x = Double.MAX_VALUE;
  for (double d : c) x = Math.min(x, d);
  return x;
}

static float min(float[] c) {
  float x = Float.MAX_VALUE;
  for (float d : c) x = Math.min(x, d);
  return x;
}

static byte min(byte[] c) {
  byte x = 127;
  for (byte d : c) if (d < x) x = d;
  return x;
}

static short min(short[] c) {
  short x = 0x7FFF;
  for (short d : c) if (d < x) x = d;
  return x;
}
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 boolean equals(Object a, Object b) {
  return a == null ? b == null : a.equals(b);
}
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 boolean inRange(int x, int n) {
  return x >= 0 && x < n;
}
static int asInt(Object o) {
  return toInt(o);
}


static String classNameToVM(String name) {
  return name.replace(".", "$");
}
static int toInt(Object o) {
  if (o == null) return 0;
  if (o instanceof Number)
    return ((Number) o).intValue();
  if (o instanceof String)
    return parseInt((String) o);
  throw fail("woot not int: " + getClassName(o));
}

static int toInt(long l) {
  if (l != (int) l) throw fail("Too large for int: " + l);
  return (int) l;
}


static class Pt {
  int x, y;
  
  Pt() {}
  Pt(Point p) {
    x = p.x;
    y = p.y;
  }
  Pt(int x, int y) {
  this.y = y;
  this.x = x;}
  
  Point getPoint() {
    return new Point(x, y);
  }
  
  public boolean equals(Object o) { return stdEq2(this, o); }
public int hashCode() { return stdHash2(this); }
  
  public String toString() {
    return x + ", " + y;
  }
}

static class Rect {
  int x, y, w, h;
  
  Rect() {}
  Rect(Rectangle r) {
    x = r.x;
    y = r.y;
    w = r.width;
    h = r.height;
  }
  Rect(int x, int y, int w, int h) {
  this.h = h;
  this.w = w;
  this.y = y;
  this.x = x;}
  
  Rectangle getRectangle() {
    return new Rectangle(x, y, w, h);
  }
  
  public boolean equals(Object o) { return stdEq2(this, o); }
public int hashCode() { return stdHash2(this); }
  
  public String toString() {
    return x + "," + y + " / " + w + "," + h;
  }
  
  int x2() { return x + w; }
  int y2() { return y + h; }
  
  boolean contains(Pt p) {
    return contains(p.x, p.y);
  }
  
  boolean contains(int _x, int _y) {
    return _x >= x && _y >= y && _x < x+w && _y < y+h;
  }
  
  boolean empty() { return w <= 0 || h <= 0; }
}

static boolean stdEq2(Object a, Object b) {
  if (a == null) return b == null;
  if (b == null) return false;
  if (a.getClass() != b.getClass()) return false;
  for (String field : allFields(a))
    if (neq(getOpt(a, field), getOpt(b, field)))
      return false;
  return true;
}
static int stdHash2(Object a) {
  if (a == null) return 0;
  return stdHash(a, toStringArray(allFields(a)));
}


static String[] toStringArray(Collection<String> c) {
  String[] a = new String[l(c)];
  Iterator<String> it = c.iterator();
  for (int i = 0; i < l(a); i++)
    a[i] = it.next();
  return a;
}

static String[] toStringArray(Object o) {
  if (o instanceof String[])
    return (String[]) o;
  else if (o instanceof Collection)
    return toStringArray((Collection<String>) o);
  else
    throw fail("Not a collection or array: " + getClassName(o));
}

static Set<String> allFields(Object o) {
  TreeSet<String> fields = new TreeSet();
  Class _c = _getClass(o);
  do {
    for (Field f : _c.getDeclaredFields())
      fields.add(f.getName());
    _c = _c.getSuperclass();
  } while (_c != null);
  return fields;
}
static int stdHash(Object a, String... fields) {
  if (a == null) return 0;
  int hash = getClassName(a).hashCode();
  for (String field : fields)
    hash = hash*2+hashCode(getOpt(a, field));
  return hash;
}
static Object getOpt(Object o, String field) {
  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;
    f.setAccessible(true);
    return f.get(o);
  } catch (Exception e) {
    throw new RuntimeException(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;
    f.setAccessible(true);
    return f.get(null);
  } catch (Exception e) {
    throw new RuntimeException(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 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 (Exception __e) { throw rethrow(__e); } }
static final WeakHashMap<Class, HashMap<String, Field>> getOpt_cache = new WeakHashMap();
static final HashMap getOpt_special = new HashMap(); // just a marker

static {
  getOpt_cache.put(Class.class, getOpt_special);
  getOpt_cache.put(String.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);
  
    if (o instanceof DynamicObject)
      return ((DynamicObject) o).fieldValues.get(field);
  
  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();
    Class _c = c;
    do {
      for (Field f : _c.getDeclaredFields()) {
        f.setAccessible(true);
        String name = f.getName();
        if (!map.containsKey(name))
          map.put(name, f);
      }
      _c = _c.getSuperclass();
    } while (_c != null);
  }
  getOpt_cache.put(c, map);
  return map;
}
static int hashCode(Object a) {
  return a == null ? 0 : a.hashCode();
}


static boolean isSubtypeOf(Class a, Class b) {
  return b.isAssignableFrom(a); // << always hated that method, let's replace it!
}

}