class Solution:
    def maxDepth(self, s: str) -> int:
        """tc O(N) sc O(1)
        ignore sign and digit, only count open paranthesis and get the max 
        
        """
        res = opens = 0
        for c in s:
            if c == '(':
                opens += 1
                res = max(res,opens)
            if c == ')':
                opens -= 1
        return res