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> List<A> itemPlusList(A a, Collection<A> l) {
  return concatLists(ll(a), l);
}
static <A> List<A> concatLists(Collection<A>... lists) {
  List<A> l = new ArrayList();
  for (Collection<A> list : lists)
    if (list != null)
      l.addAll(list);
  return l;
}

static <A> List<A> concatLists(Collection<? extends Collection<A>> lists) {
  List<A> l = new ArrayList();
  for (Collection<A> list : lists)
    if (list != null)
      l.addAll(list);
  return l;
}

static <A> List<A> ll(A... a) {
  ArrayList l = new ArrayList(a.length);
  for (A x : a) l.add(x);
  return l;
}

}