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 A assertEqualsOneOfVerbose(A x, A... l) {
for (A y : unnull(l))
if (eq(x, y))
{ print("OK: " + x); return x; }
throw fail(x + " not found in " + asList(l));
}
static String unnull(String s) {
return s == null ? "" : s;
}
static Collection unnull(Collection l) {
return l == null ? emptyList() : l;
}
static List unnull(List l) {
return l == null ? emptyList() : l;
}
static Map unnull(Map l) {
return l == null ? emptyMap() : l;
}
static Iterable unnull(Iterable i) {
return i == null ? emptyList() : i;
}
static A[] unnull(A[] a) {
return a == null ? (A[]) emptyObjectArray() : a;
}
static BitSet unnull(BitSet b) {
return b == null ? new BitSet() : b;
}
//ifclass Symbol
static Pair unnull(Pair p) {
return p != null ? p : new Pair(null, null);
}
static boolean eq(Object a, Object b) {
return a == b || (a == null ? b == null : b != null && a.equals(b));
}
static volatile StringBuffer local_log = new StringBuffer(); // not redirected
static volatile Appendable print_log = local_log; // might be redirected, e.g. to main bot
// in bytes - will cut to half that
static volatile int print_log_max = 1024*1024;
static volatile int local_log_max = 100*1024;
static boolean print_silent = false; // total mute if set
static Object print_byThread_lock = new Object();
static volatile ThreadLocal