import java.util.Stack;
public class MyQueue {
private Stack stack1;
private Stack stack2;
/** Initialize your data structure here. */
public MyQueue() {
stack1 = new Stack<>();
stack2 = new Stack<>();
}
/** Push element x to the back of queue. */
public void push(int x) {
stack1.push(x);
}
/** Removes the element from in front of queue and returns that element. */
public int pop() {
peek();
return stack2.pop();
}
/** Get the front element. */
public int peek() {
if (stack2.empty()) {
while (!stack1.empty()) {
stack2.push(stack1.pop());
}
}
return stack2.peek();
}
/** Returns whether the queue is empty. */
public boolean empty() {
return stack1.empty() && stack2.empty();
}
}