import java.util.Stack;

class MyQueue {
  private Stack<Integer> stack1;
  private Stack<Integer> stack2;

  public MyQueue() {
      stack1 = new Stack<Integer>();
      stack2 = new Stack<Integer>();
  }
  
  public void push(int x) {
      stack1.push(x);
  }
  
  public int pop() {
      if (stack2.empty()) {
        while (!stack1.empty()) {
          Integer popped = stack1.pop();
          stack2.push(popped);
        }
      }

      // assumption: stack2 is not empty, call to pop() valid and not trying to
      // bring up exception for not having anything in queue
      return stack2.pop();
  }

  public int peek() {
    if (stack2.empty()) {
      while (!stack1.empty()) {
        Integer popped = stack1.pop();
        stack2.push(popped);
      }
    }

    return stack2.peek();
  }
  
  public boolean empty() {
      return stack1.empty() && stack2.empty();
  }
}

/**
* Your MyQueue object will be instantiated and called as such:
* MyQueue obj = new MyQueue();
* obj.push(x);
* int param_2 = obj.pop();
* int param_3 = obj.peek();
* boolean param_4 = obj.empty();
*/