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class MinStack:

    def __init__(self):
        """
        initialize your data structure here.
        """
        self.stack=[]
        self.helper=[]
    def push(self, x: int) -> None:
        if self.helper==[] or self.helper[-1]>=x:
            self.helper.append(x)
        self.stack.append(x)

    def pop(self) -> None:
        a=self.stack.pop()
        if self.helper and a==self.helper[-1]:
            self.helper.pop()

    def top(self) -> int:
        return self.stack[-1]

    def getMin(self) -> int:
        return self.helper[-1]



# Your MinStack object will be instantiated and called as such:
# obj = MinStack()
# obj.push(x)
# obj.pop()
# param_3 = obj.top()
# param_4 = obj.getMin()