class MyQueue {

/** Initialize your data structure here. */
public MyQueue(){

}
Stack<Integer> s1=new Stack<>();
Stack<Integer> s2=new Stack<>();


/** Push element x to the back of queue. */
public void push(int x) {
    s1.push(x);

}

/** Removes the element from in front of queue and returns that element. */
public int pop() {
    if(s1.isEmpty()){
       return -1; 
    }

    while(!s1.isEmpty()){
        s2.push(s1.pop());
    }
    int ret=(Integer)s2.pop();
    while(!s2.isEmpty()){
        s1.push(s2.pop());
    }
    return ret;
}

public int peek(){

      if(s1.isEmpty()){
       return -1; 
    }

    while(!s1.isEmpty()){
        s2.push(s1.pop());
    }
    int ret=(Integer)s2.peek();
    while(!s2.isEmpty()){
        s1.push(s2.pop());
    }
    return ret;
}

/** Returns whether the queue is empty. */
public boolean empty() {
    return s1.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();
/