#
# 
# @param s string字符串 
# @return bool布尔型
#
class Solution:
    def isValid(self , s ):
        # write code here
        stack = [ ]

        if len(s) == 1  or len(s)%2 !=0:
            return False
        else:
            stack = []
            dict ={'(':')','[':']','{':'}'}
            for i in s:
                if i in dict:
                    stack.append(dict.get(i))
                else:
                    if stack:
                        if i== stack[-1]:
                            stack.pop()

            if len(stack)==0: 
                return True
            else:
                return False