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 {
public static void main(final String[] args) throws Exception {
  print(html_addTargetBlank("<a href=\"bla\">bla</a> <a href=\"blabla\" target=\"_blank\">ok</a> <a name=\"test\"></a>"));
}
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 String html_addTargetBlank(String html) {
  List<String> tok = htmlTok(html);
  for (int i = 1; i < l(tok); i += 2) {
    String t = tok.get(i);
    if (isTag(t, "a")) {
      Map<String, String> map = htmlParams(t);
      if (map.containsKey("href")) {
        map.put("target", "_blank");
        tok.set(i, hopeningTag("a", mapToParams(map)));
      }
    }
  }
  return join(tok);
}
static RuntimeException asRuntimeException(Throwable t) {
  return t instanceof RuntimeException ? (RuntimeException) t : new RuntimeException(t);
}
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 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 List<String> htmlTok(String s) {
  return htmlcoarsetok(s);
}
static boolean isFalse(Object o) {
  return eq(false, o);
}
static String hopeningTag(String tag, Object... params) {
  StringBuilder buf = new StringBuilder();
  buf.append("<" + tag);
  for (int i = 0; i < l(params); i += 2) {
    String name = (String) get(params, i);
    Object val = get(params, i+1);
    if (nempty(name) && val != null) {
      String s = str(val);
      if (!empty(s))
        buf.append(" " + name + "=" + htmlQuote(s));
    }
  }
  buf.append(">");
  return str(buf);
}
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 boolean isTag(String token, String tag) {
  return token.regionMatches(true, 0, "<" + tag + " ", 0, tag.length()+2)
    || token.regionMatches(true, 0, "<" + tag + ">", 0, tag.length()+2);
}
static Object[] mapToParams(Map map) {
  return mapToObjectArray(map);
}
static Map<String, String> htmlParams(String tag) {
  return getHtmlTagParameters(tag);
}
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 Map synchroMap() {
  return synchroHashMap();
}

static <A, B> Map<A, B> synchroMap(Map<A, B> map) {
  return Collections.synchronizedMap(map);
}
// TODO: process CDATA?

static List<String> htmlcoarsetok(String s) {
  List<String> tok = new ArrayList<String>();
  int l = s.length();
  
  int i = 0;
  while (i < l) {
    int j = i;
    char c;
    
    // scan for non-tags
    while (j < l) {
      if (s.charAt(j) != '<')
        // regular character
        ++j;
      else if (s.substring(j, Math.min(j+4, l)).equals("<!--")) {
        // HTML comment
        j = j+4;
        do ++j; while (j < l && !s.substring(j, Math.min(j+3, l)).equals("-->"));
        j = Math.min(j+3, l);
      } else
        // it's a tag
        break;
    }
    tok.add(s.substring(i, j));
    i = j;
    if (i >= l) break;
    c = s.charAt(i);

    // scan for tags
    if (c == '<') {
      ++j;
      
      while (j < l && s.charAt(j) != '>') ++j; // TODO: strings?
      if (j < l) ++j;
    }

    tok.add(s.substring(i, j));
    i = j;
  }
  
  if ((tok.size() % 2) == 0) tok.add("");
  return tok;
}
static boolean getHtmlTagParameters_debug;

static Map<String, String> getHtmlTagParameters(String tag) {
  if (empty(tag)) return null;
  List<String> tok = codeTokens(tok_joinMinusIdentifiers(htmlFineTok(tag)));
  if (getHtmlTagParameters_debug)
    printStruct(tok);
  assertEquals("<", tok.get(0));
  int i = 1;
  if (eq(tok.get(1), "/")) ++i;
  String name = tok.get(i++);
  if (!isMinusIdentifier(name))
    throw fail(tag + " (" + name + ")");
  Map<String,String> map = new HashMap();
  while (i < l(tok)) {
    String t = tok.get(i);
    if (eqOneOf(t, "/", ">")) break;
    if (!isMinusIdentifier(t))
      throw fail(tag + " (" + t + ")");
    ++i;
    String value = "1";
    if (eq(tok.get(i), "=")) {
      ++i;
      value = htmlunquote(tok.get(i++));
    }
    map.put(t, value);
  }
  return map;
}
static String htmlQuote(String s) {
  return "\"" + htmlencode(s) + "\"";
}
static <A, B> Map<A, B> newWeakHashMap() {
  return _registerWeakMap(synchroMap(new WeakHashMap()));
}
static Object[] mapToObjectArray(Map map) {
  List l = new ArrayList();
  for (Object o : keys(map)) {
    l.add(o);
    l.add(map.get(o));
  }
  return toObjectArray(l);
}
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; }
// 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());
}

// 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 RuntimeException rethrow(Throwable e) {
  throw asRuntimeException(e);
}
static Thread currentThread() {
  return Thread.currentThread();
}
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 boolean eq(Object a, Object b) {
  return a == null ? b == null : a == b || a.equals(b);
}
static String str(Object o) {
  return o == null ? "null" : o.toString();
}

static String str(char[] c) {
  return new String(c);
}
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 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 boolean isMinusIdentifier(String s) {
  if (empty(s)) return false;
  if (!Character.isJavaIdentifierStart(s.charAt(0))
    && !s.startsWith("-"))
    return false;
  for (int i = 1; i < s.length(); i++)
    if (!Character.isJavaIdentifierPart(s.charAt(i)) && s.charAt(i) != '-')
      return false;
  return true;
}
static boolean eqOneOf(Object o, Object... l) {
  for (Object x : l) if (eq(o, x)) return true; return false;
}
static String getType(Object o) {
  return getClassName(o);
}
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 List<String> htmlFineTok(String s) {
  List<String> tok = 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
        break;
    }
    
    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
    
    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
      ++j;
      
    tok.add(quickSubstring(s, i, j));
    ++n;
    i = j;
  }
  
  if ((tok.size() % 2) == 0) tok.add("");
  return tok;
}
static <A> A printStruct(String prefix, A a) {
  printStructure(prefix, a);
  return a;
}

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

static <A, B> Set<A> keys(Map<A, B> map) {
  return map == null ? new HashSet() : map.keySet();
}

static Set keys(Object map) {
  return keys((Map) map);
}




static List<String> tok_joinMinusIdentifiers(List<String> tok) {
  for (int i = 1; i+4 < l(tok); i += 2)
    if (isMinusIdentifier(get(tok, i)) && eq(get(tok, i+2), "-") && isIdentifier(get(tok, i+4))) {
      replaceSublist(tok, i, i+5, ll(join(subList(tok, i, i+5))));
      i -= 2;
    }
  return tok;
}
static String htmlunquote(String s) {
  if (s.startsWith("'") && s.endsWith("'") && s.length() >= 2
    || s.startsWith("\"") && s.endsWith("\"") && s.length() >= 2)
    s = s.substring(1, s.length()-1);
  return htmldecode(s);
}
static Object[] toObjectArray(Collection c) {
  List l = asList(c);
  return l.toArray(new Object[l.size()]);
}

static List<String> codeTokens(List<String> tok) {
  return codeTokensOnly(tok);
}
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 <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;
}
  // automagically encode a whole map (keys+values)
  static Map htmlencode(Map o) {
    HashMap bla = new HashMap();
    for (Object key : keys(o)) {
      Object value = o.get(key);
      bla.put(htmlencode(key), htmlencode(value));
    }
    return bla;
  }

  static String htmlencode(Object o) {
    return htmlencode(string(o));
  }
  
  static String htmlencode(String s) {
    if (s == null) return "";
    StringBuilder out = new StringBuilder(Math.max(16, s.length()));
    for (int i = 0; i < s.length(); i++) {
        char c = s.charAt(i);
        if (c > 127 || c == '"' || c == '<' || c == '>' || c == '&') {
            out.append("&#");
            out.append((int) c);
            out.append(';');
        } else {
            out.append(c);
        }
    }
    return out.toString();
  }
static Map synchroHashMap() {
  return Collections.synchronizedMap(new HashMap());
}

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 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 isIdentifier(String s) {
  return isJavaIdentifier(s);
}
static <A> List<A> ll(A... a) {
  return litlist(a);
}
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;
}
static Class javax() {
  return getJavaX();
}
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 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> replaceSublist(List<A> l, List<A> x, List<A> y) {
  if (x == null) return l;
  
  int i = 0;
  while (true) {
    i = indexOfSubList(l, x, i);
    if (i < 0) break;
    
    // It's inefficient :D
    for (int j = 0; j < l(x); j++) l.remove(i);
    l.addAll(i, y);
    i += l(y);
  }
  return l;
}

static <A> List<A> replaceSublist(List<A> l, int fromIndex, int toIndex, List<A> y) {
  // inefficient
  while (toIndex > fromIndex) l.remove(--toIndex);
  l.addAll(fromIndex, y);
  return l;
}
  static List<String> codeTokensOnly(List<String> tok) {
    List<String> l = new ArrayList();
    for (int i = 1; i < tok.size(); i += 2)
      l.add(tok.get(i));
    return l;
  }
static void printException(Throwable e) {
  printStackTrace(e);
}
static String getClassName(Object o) {
  return o == null ? "null" : o instanceof Class ? ((Class) o).getName() : o.getClass().getName();
}
static String quickSubstring(String s, int i, int j) {
  if (i == j) return "";
  return s.substring(i, j);
}
static String string(Object o) {
  return String.valueOf(o);
}
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> List<A> subList(List<A> l, int startIndex) {
  return subList(l, startIndex, l(l));
}

static <A> List<A> subList(List<A> l, int startIndex, int endIndex) {
  startIndex = max(0, min(l(l), startIndex));
  endIndex = max(0, min(l(l), endIndex));
  if (startIndex > endIndex) return litlist();
  return l.subList(startIndex, endIndex);
}


static String htmldecode(final String input) {
  if (input == null) return null;
  
  final int MIN_ESCAPE = 2;
  final int MAX_ESCAPE = 6;

  StringWriter writer = null;
  int len = input.length();
  int i = 1;
  int st = 0;
  while (true) {
      // look for '&'
      while (i < len && input.charAt(i-1) != '&')
          i++;
      if (i >= len)
          break;

      // found '&', look for ';'
      int j = i;
      while (j < len && j < i + MAX_ESCAPE + 1 && input.charAt(j) != ';')
          j++;
      if (j == len || j < i + MIN_ESCAPE || j == i + MAX_ESCAPE + 1) {
          i++;
          continue;
      }

      // found escape 
      if (input.charAt(i) == '#') {
          // numeric escape
          int k = i + 1;
          int radix = 10;

          final char firstChar = input.charAt(k);
          if (firstChar == 'x' || firstChar == 'X') {
              k++;
              radix = 16;
          }

          try {
              int entityValue = Integer.parseInt(input.substring(k, j), radix);

              if (writer == null) 
                  writer = new StringWriter(input.length());
              writer.append(input.substring(st, i - 1));

              if (entityValue > 0xFFFF) {
                  final char[] chrs = Character.toChars(entityValue);
                  writer.write(chrs[0]);
                  writer.write(chrs[1]);
              } else {
                  writer.write(entityValue);
              }

          } catch (NumberFormatException ex) { 
              i++;
              continue;
          }
      }
      else {
          // named escape
          CharSequence value = htmldecode_lookupMap.get(input.substring(i, j));
          if (value == null) {
              i++;
              continue;
          }

          if (writer == null) 
              writer = new StringWriter(input.length());
          writer.append(input.substring(st, i - 1));

          writer.append(value);
      }

      // skip escape
      st = j + 1;
      i = st;
  }

  if (writer != null) {
      writer.append(input.substring(st, len));
      return writer.toString();
  }
  return input;
}

private static final String[][] htmldecode_ESCAPES = {
    {"\"",     "quot"}, // " - double-quote
    {"&",      "amp"}, // & - ampersand
    {"<",      "lt"}, // < - less-than
    {">",      "gt"}, // > - greater-than

    // Mapping to escape ISO-8859-1 characters to their named HTML 3.x equivalents.
    {"\u00A0", "nbsp"}, // non-breaking space
    {"\u00A1", "iexcl"}, // inverted exclamation mark
    {"\u00A2", "cent"}, // cent sign
    {"\u00A3", "pound"}, // pound sign
    {"\u00A4", "curren"}, // currency sign
    {"\u00A5", "yen"}, // yen sign = yuan sign
    {"\u00A6", "brvbar"}, // broken bar = broken vertical bar
    {"\u00A7", "sect"}, // section sign
    {"\u00A8", "uml"}, // diaeresis = spacing diaeresis
    {"\u00A9", "copy"}, // copyright sign
    {"\u00AA", "ordf"}, // feminine ordinal indicator
    {"\u00AB", "laquo"}, // left-pointing double angle quotation mark = left pointing guillemet
    {"\u00AC", "not"}, // not sign
    {"\u00AD", "shy"}, // soft hyphen = discretionary hyphen
    {"\u00AE", "reg"}, // registered trademark sign
    {"\u00AF", "macr"}, // macron = spacing macron = overline = APL overbar
    {"\u00B0", "deg"}, // degree sign
    {"\u00B1", "plusmn"}, // plus-minus sign = plus-or-minus sign
    {"\u00B2", "sup2"}, // superscript two = superscript digit two = squared
    {"\u00B3", "sup3"}, // superscript three = superscript digit three = cubed
    {"\u00B4", "acute"}, // acute accent = spacing acute
    {"\u00B5", "micro"}, // micro sign
    {"\u00B6", "para"}, // pilcrow sign = paragraph sign
    {"\u00B7", "middot"}, // middle dot = Georgian comma = Greek middle dot
    {"\u00B8", "cedil"}, // cedilla = spacing cedilla
    {"\u00B9", "sup1"}, // superscript one = superscript digit one
    {"\u00BA", "ordm"}, // masculine ordinal indicator
    {"\u00BB", "raquo"}, // right-pointing double angle quotation mark = right pointing guillemet
    {"\u00BC", "frac14"}, // vulgar fraction one quarter = fraction one quarter
    {"\u00BD", "frac12"}, // vulgar fraction one half = fraction one half
    {"\u00BE", "frac34"}, // vulgar fraction three quarters = fraction three quarters
    {"\u00BF", "iquest"}, // inverted question mark = turned question mark
    {"\u00C0", "Agrave"}, // ? - uppercase A, grave accent
    {"\u00C1", "Aacute"}, // ? - uppercase A, acute accent
    {"\u00C2", "Acirc"}, // ? - uppercase A, circumflex accent
    {"\u00C3", "Atilde"}, // ? - uppercase A, tilde
    {"\u00C4", "Auml"}, // ? - uppercase A, umlaut
    {"\u00C5", "Aring"}, // ? - uppercase A, ring
    {"\u00C6", "AElig"}, // ? - uppercase AE
    {"\u00C7", "Ccedil"}, // ? - uppercase C, cedilla
    {"\u00C8", "Egrave"}, // ? - uppercase E, grave accent
    {"\u00C9", "Eacute"}, // ? - uppercase E, acute accent
    {"\u00CA", "Ecirc"}, // ? - uppercase E, circumflex accent
    {"\u00CB", "Euml"}, // ? - uppercase E, umlaut
    {"\u00CC", "Igrave"}, // ? - uppercase I, grave accent
    {"\u00CD", "Iacute"}, // ? - uppercase I, acute accent
    {"\u00CE", "Icirc"}, // ? - uppercase I, circumflex accent
    {"\u00CF", "Iuml"}, // ? - uppercase I, umlaut
    {"\u00D0", "ETH"}, // ? - uppercase Eth, Icelandic
    {"\u00D1", "Ntilde"}, // ? - uppercase N, tilde
    {"\u00D2", "Ograve"}, // ? - uppercase O, grave accent
    {"\u00D3", "Oacute"}, // ? - uppercase O, acute accent
    {"\u00D4", "Ocirc"}, // ? - uppercase O, circumflex accent
    {"\u00D5", "Otilde"}, // ? - uppercase O, tilde
    {"\u00D6", "Ouml"}, // ? - uppercase O, umlaut
    {"\u00D7", "times"}, // multiplication sign
    {"\u00D8", "Oslash"}, // ? - uppercase O, slash
    {"\u00D9", "Ugrave"}, // ? - uppercase U, grave accent
    {"\u00DA", "Uacute"}, // ? - uppercase U, acute accent
    {"\u00DB", "Ucirc"}, // ? - uppercase U, circumflex accent
    {"\u00DC", "Uuml"}, // ? - uppercase U, umlaut
    {"\u00DD", "Yacute"}, // ? - uppercase Y, acute accent
    {"\u00DE", "THORN"}, // ? - uppercase THORN, Icelandic
    {"\u00DF", "szlig"}, // ? - lowercase sharps, German
    {"\u00E0", "agrave"}, // ? - lowercase a, grave accent
    {"\u00E1", "aacute"}, // ? - lowercase a, acute accent
    {"\u00E2", "acirc"}, // ? - lowercase a, circumflex accent
    {"\u00E3", "atilde"}, // ? - lowercase a, tilde
    {"\u00E4", "auml"}, // ? - lowercase a, umlaut
    {"\u00E5", "aring"}, // ? - lowercase a, ring
    {"\u00E6", "aelig"}, // ? - lowercase ae
    {"\u00E7", "ccedil"}, // ? - lowercase c, cedilla
    {"\u00E8", "egrave"}, // ? - lowercase e, grave accent
    {"\u00E9", "eacute"}, // ? - lowercase e, acute accent
    {"\u00EA", "ecirc"}, // ? - lowercase e, circumflex accent
    {"\u00EB", "euml"}, // ? - lowercase e, umlaut
    {"\u00EC", "igrave"}, // ? - lowercase i, grave accent
    {"\u00ED", "iacute"}, // ? - lowercase i, acute accent
    {"\u00EE", "icirc"}, // ? - lowercase i, circumflex accent
    {"\u00EF", "iuml"}, // ? - lowercase i, umlaut
    {"\u00F0", "eth"}, // ? - lowercase eth, Icelandic
    {"\u00F1", "ntilde"}, // ? - lowercase n, tilde
    {"\u00F2", "ograve"}, // ? - lowercase o, grave accent
    {"\u00F3", "oacute"}, // ? - lowercase o, acute accent
    {"\u00F4", "ocirc"}, // ? - lowercase o, circumflex accent
    {"\u00F5", "otilde"}, // ? - lowercase o, tilde
    {"\u00F6", "ouml"}, // ? - lowercase o, umlaut
    {"\u00F7", "divide"}, // division sign
    {"\u00F8", "oslash"}, // ? - lowercase o, slash
    {"\u00F9", "ugrave"}, // ? - lowercase u, grave accent
    {"\u00FA", "uacute"}, // ? - lowercase u, acute accent
    {"\u00FB", "ucirc"}, // ? - lowercase u, circumflex accent
    {"\u00FC", "uuml"}, // ? - lowercase u, umlaut
    {"\u00FD", "yacute"}, // ? - lowercase y, acute accent
    {"\u00FE", "thorn"}, // ? - lowercase thorn, Icelandic
    {"\u00FF", "yuml"}, // ? - lowercase y, umlaut
    {"\u2013", "ndash"},
    {"\u2018", "lsquo"},
    {"\u2019", "rsquo"},
    {"\u201D", "rdquo"},
    {"\u201C", "ldquo"},
    {"\u2014", "mdash"},
    
    {"'", "apos"}, // the controversial (but who cares!) &apos;
      // stackoverflow.com/questions/2083754/why-shouldnt-apos-be-used-to-escape-single-quotes
  };

private static final HashMap<String, CharSequence> htmldecode_lookupMap;
static {
    htmldecode_lookupMap = new HashMap<String, CharSequence>();
    for (final CharSequence[] seq : htmldecode_ESCAPES) 
        htmldecode_lookupMap.put(seq[1].toString(), seq[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 <A> int indexOfSubList(List<A> x, List<A> y) {
  return indexOfSubList(x, y, 0);
}

static <A> int indexOfSubList(List<A> x, List<A> y, int i) {
  outer: for (; i+l(y) <= l(x); i++) {
    for (int j = 0; j < l(y); j++)
      if (neq(x.get(i+j), y.get(j)))
        continue outer;
    return i;
  }
  return -1;
}

static <A> int indexOfSubList(List<A> x, A[] y, int i) {
  outer: for (; i+l(y) <= l(x); i++) {
    for (int j = 0; j < l(y); j++)
      if (neq(x.get(i+j), y[j]))
        continue outer;
    return i;
  }
  return -1;
}
static Object callFunction(Object f, Object... args) {
  return callF(f, args);
}
// 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 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 boolean isJavaIdentifier(String s) {
  if (empty(s) || !Character.isJavaIdentifierStart(s.charAt(0)))
    return false;
  for (int i = 1; i < s.length(); i++)
    if (!Character.isJavaIdentifierPart(s.charAt(i)))
      return false;
  return true;
}
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 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 <A> ArrayList<A> litlist(A... a) {
  return new ArrayList<A>(Arrays.asList(a));
}
static String structureForUser(Object o) {
  return beautifyStructure(struct_noStringSharing(o));
}
static boolean endsWithLetter(String s) {
  return nempty(s) && isLetter(last(s));
}
static Class __javax;

static Class getJavaX() {
  return __javax;
}
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 String struct_noStringSharing(Object o) {
  structure_Data d = new structure_Data();
  d.noStringSharing = true;
  return structure(o, d);
}
static WeakHashMap<Class, ArrayList<Method>> callF_cache = new WeakHashMap();



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 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 <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 String beautifyStructure(String s) {
  return structure_addTokenMarkers(s);
}
static boolean isLetter(char c) {
  return Character.isLetter(c);
}


static volatile Throwable lastException_lastException;

static Throwable lastException() {
  return lastException_lastException;
}

static void lastException(Throwable e) {
  lastException_lastException = e;
}
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 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 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 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 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 + "'";
}

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;
}
// 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 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 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 String boolArrayToHex(boolean[] a) {
  return bytesToHex(boolArrayToBytes(a));
}
static boolean endsWithLetterOrDigit(String s) {
  return nempty(s) && isLetterOrDigit(lastCharacter(s));
}
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); }


  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 Class mc() {
  return main.class;
}
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 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 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 int parseInt(String s) {
  return empty(s) ? 0 : Integer.parseInt(s);
}

static int parseInt(char c) {
  return Integer.parseInt(str(c));
}
static <A> A popLast(List<A> l) {
  return liftLast(l);
}
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 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 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 <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 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 char lastCharacter(String s) {
  return empty(s) ? 0 : s.charAt(l(s)-1);
}
static boolean isLetterOrDigit(char c) {
  return Character.isLetterOrDigit(c);
}
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 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 int lastIndexOf(String a, String b) {
  return a == null || b == null ? -1 : a.lastIndexOf(b);
}


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;}
}
}