class MyQueue {

private final Deque<Integer> st1;

private final Deque<Integer> st2;

/** Initialize your data structure here. */

public MyQueue() {

st1 = new ArrayDeque<>();

st2 = new ArrayDeque<>();

}

/** Push element x to the back of queue. */

public void push(int x) {

st1.push(x);

}

/** Removes the element from in front of queue and returns that element. */

public int pop() {

if(st2.isEmpty()) {

move();

}

return st2.pop();

}

private void move() {

while(!st1.isEmpty()) {

st2.push(st1.pop());

}

}

/** Get the front element. */

public int peek() {

if(st2.isEmpty()) {

move();

}

return st2.peek();

}

/** Returns whether the queue is empty. */

public boolean empty() {

return st2.isEmpty() && st1.isEmpty();

}

}

/**

* 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();

*/