class MyQueue {
private:
stack[HTML_REMOVED] in, out;

void in2out() {
    while (!in.empty()) {
        out.push(in.top());
        in.pop();
    }
}

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

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

/** 将队首的元素弹出，并返回该元素 */
int pop() {
    if(out.empty()){
        in2out();
    }
    int res = out.top();
    out.pop();
    return res;
}

/** 返回队首元素 */
int peek() {
    if(out.empty()){
        in2out();
    }
    return out.top();
}

/**  返回队列是否为空 */
bool empty() {
    return in.empty() && out.empty();
}

};

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