import java.util.Stack;

 public class T007 {

     public static void main(String[] args) {

         Queue q = new Queue();

         q.stack1 = new Stack();

         q.stack2 = new Stack();

         q.appendTail(1);

         System.out.println(q.stack1.toString());

         System.out.println(q.stack2.toString());

         q.appendTail(2);

         q.appendTail(3);

         q.deleteHead();

         System.out.println(q.stack1.toString());

         System.out.println(q.stack2.toString());

     }

     public static class Queue {

         private Stack<Integer> stack1;

         private Stack<Integer> stack2;

         public void appendTail(int e) {

             stack1.push(e);

         }

         public void deleteHead() {

             if (stack2.size() <= 0) {

                 while (stack1.size() > 0) {

                     int data = stack1.peek();

                     stack1.pop();

                     stack2.push(data);

                 }

             }

             if (stack2.size() == 0)

                 System.out.println("queue is empty");

             int head = stack2.peek();

             stack2.pop();

         }

     }

 }