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class MyStack:

    def __init__(self):
        """
        Initialize your data structure here.
        """
        self.queue1 = deque()
        self.queue2 = deque()

    def push(self, x: int) -> None:
        """
        Push element x onto stack.
        """
        self.queue2.append(x)
        while self.queue1:
            self.queue2.append(self.queue1.popleft())
        self.queue2,self.queue1=self.queue1,self.queue2

    def pop(self) -> int:
        """
        Removes the element on top of the stack and returns that element.
        """
        if not self.queue1:
            return 0
        return self.queue1.popleft()

    def top(self) -> int:
        """
        Get the top element.
        """
        if not self.queue1:
            return 0
        return self.queue1[0]

    def empty(self) -> bool:
        """
        Returns whether the stack is empty.
        """
        return len(self.queue1)==0