Implement Stack using Queues

class MyQueue:

    def __init__(self):
        self.queue = deque()
        self.sz = 0

    def enqueue(self, x):
        self.queue.append(x)
        self.sz += 1

    def dequeue(self):
        self.sz -= 1
        return self.queue.popleft()

    def front(self):
        return self.queue[0]

    def empty(self):
        return self.sz == 0

    def size(self):
        return self.sz

class MyStack:

    def __init__(self):
        self.mainQ = MyQueue()

    def push(self, x: int) -> None:
        self.sz = self.mainQ.size()
        self.mainQ.enqueue(x)
        for itr in range(self.sz):
            head = self.mainQ.dequeue()
            self.mainQ.enqueue(head)

    def pop(self) -> int:
        return self.mainQ.dequeue()

    def top(self) -> int:
        return self.mainQ. front()

    def empty(self) -> bool:
        return self.mainQ.empty()