class MinStack:

    def __init__(self):
        self.stack = []
        self.min_stack = []

    def push(self, val: int) -> None:
        self.stack.append(val)
        if len(self.min_stack) == 0: # min stack empty
            self.min_stack.append(val)
        else:
            self.min_stack.append(min(val, self.min_stack[-1])) # "new smallest" or "copy last smallest"

    def pop(self) -> None:
        result = self.stack.pop()
        del self.min_stack[-1] 

        return result

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


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


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