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, B extends A> void addIfInstanceOf(Collection<A> l, Class<B> c, Object a) {
  if (l != null && instanceOf(c, a)) l.add((A) a);
}
static boolean instanceOf(Object o, String className) {
  if (o == null) return false;
  String c = o.getClass().getName();
  return eq(c, className) || eq(c, "main$" + className);
}

static boolean instanceOf(Object o, Class c) {
  if (c == null) return false;
  return c.isInstance(o);
}


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




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

static String str(char[] c) {
  return new String(c);
}

}