class Solution:
    def isValid(self, s):
        stack = []
        for char in s: 
            if char == '{' or char == '[' or char == '(':
                stack.append(char)
            else:
                popped = stack.pop()
                if popped == '{' and char != '}':
                    return False
                elif popped == '[' and char != ']':
                    return False
                elif popped == '(' and char != ')':
                    return False
                   
        return len(stack) == 0