import java.util.*;
import java.util.zip.*;
import java.util.List;
import java.util.regex.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;
import java.util.concurrent.locks.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
import javax.swing.table.*;
import java.io.*;
import java.net.*;
import java.lang.reflect.*;
import java.lang.ref.*;
import java.lang.management.*;
import java.security.*;
import java.security.spec.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.imageio.*;
import java.math.*;
class main {
static void test_allDistinctPairs_inOrder() {
assertEqualsVerbose(ll(pair("a", "b"), pair("a", "c"), pair("b", "c")),
allDistinctPairs_inOrder(ll("a", "b", "c")));
}
static A assertEqualsVerbose(Object x, A y) {
assertEqualsVerbose((String) null, x, y);
return y;
}
static A assertEqualsVerbose(String msg, Object x, A y) {
if (!eq(x, y)) {
throw fail((msg != null ? msg + ": " : "") + /*sfu*/(y) + " != " + /*sfu*/(x));
} else
print("OK: " + /*sfu*/(x));
return y;
}
static List ll(A... a) {
ArrayList l = new ArrayList(a.length);
if (a != null) for (A x : a) l.add(x);
return l;
}
static Pair pair(A a, B b) {
return new Pair(a, b);
}
static Pair pair(A a) {
return new Pair(a, a);
}
static List> allDistinctPairs_inOrder(List l) {
return lambdaMap(__19 -> listToPair(__19),allSubsetsOfSize_iterator(2, l));
}
static boolean eq(Object a, Object b) {
return a == b || (a == null ? b == null : b != null && 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 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