HTMLify

class Solution:
    def isValid(self, s: str) -> bool:
        stack = []
        m = {
            ')': '(',
            '}': '{',
            ']': '[',
        }
        for c in s:
            if c in ")}]" and (not stack or stack[-1] != m[c]):
                return False
            stack.append(c)
            if c in ")}]":
                stack.pop()
                stack.pop()
        if stack:
            return False
        return True