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 List fromSimplyLinkedList(SimplyLinkedList sll) {
List l = new ArrayList();
while (sll != null) {
l.add(sll.head);
sll = sll.tail;
}
return l;
}
static class SimplyLinkedList {
A head;
SimplyLinkedList tail;
static SimplyLinkedList cons(B head, SimplyLinkedList tail) {
SimplyLinkedList l = new SimplyLinkedList();
l.head = head;
l.tail = tail;
return l;
}
}
}