#
# 
# @param s string字符串 
# @return bool布尔型
#
class Solution:
    def isValid(self , s ):
        # write code here
        dic = {'(':')','{' :"}",'[':']'}
        first = []
        for ss in s:
            if ss in dic.keys():
                first.append(ss)
            if ss in dic.values():
                if len(first) == 0:
                    return False
                tem = first.pop()
                if ss == dic[tem]:
                    continue
                else:
                    return False
        return True if len(first)==0 else False