class MinStack:

    def __init__(self):
        """
        initialize your data structure here.
        """
        self.data = []
        

    def push(self, x):
        """
        :type x: int
        :rtype: void
        """
        if len(self.data) == 0:
            return self.data.append((x,x))
        else:
            min_num=self.data[-1][1]
            return  self.data.append((x,x)) if min_num > x else self.data.append((x,min_num))
        
        

    def pop(self):
        """
        :rtype: void
        """
        return self.data.pop()

    def top(self):
        """
        :rtype: int
        """
        return self.data[-1][0]
        

    def getMin(self):
        """
        :rtype: int
        """
        return self.data[-1][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()