Implement the following operations of a queue using stacks.

push(x) – Push element x to the back of queue.
pop() – Removes the element from in front of queue.
peek() – Get the front element.
empty() – Return whether the queue is empty.

Notes:
You must use only standard operations of a stack – which means only push to top, peek/pop from top, size, and is empty operations are valid.
Depending on your language, stack may not be supported natively. You may simulate a stack by using a list or deque (double-ended queue), as long as you use only standard operations of a stack.
You may assume that all operations are valid (for example, no pop or peek operations will be called on an empty queue).

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class MyQueue {
    Stack<Integer> input = new Stack<Integer>();
    Stack<Integer> output = new Stack<Integer>();
    
    // Push element x to the back of queue.
    public void push(int x) {
        input.push(x);
    }

    // Removes the element from in front of queue.
    public void pop() {
        peek();
        output.pop();
    }

    // Get the front element.
    public int peek() {
        if (output.empty()){
            while (!input.empty()){
                output.push(input.pop());
            }
        }
        return output.peek();
    }

    // Return whether the queue is empty.
    public boolean empty() {
        return input.empty() && output.empty();
    }
}