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> matrixToList(Matrix<A> m) {
  if (m == null) return null;
  int w = m.getWidth(), h = m.getHeight(), n = w*h;
  
  return new RandomAccessAbstractList<A>() {
    public int size() { return n; }
    
    public A get(int i) {
      return m.get(i % w, i / w);
    }
    
    public A set(int i, A val) {
      A old = m.get(i % w, i % h);
      m.set(i % w, i / w, val);
      return old;
    }
  };
}
interface Matrix<A> {
  public int getWidth();
  public int getHeight();
  public A get(int x, int y);
  public void set(int x, int y, A a);
}
abstract static class RandomAccessAbstractList<A> extends AbstractList<A> implements RandomAccess {
}

}