class Solution {

public:

    bool isValid(string s) {

        if(s.size()<||s.size()%!=)return false;

        unordered_map<char,char>hashmap;

        hashmap['(']=')';

        hashmap['[']=']';

        hashmap['{']='}';

        if(s.size()==)return hashmap[s[]]==s[];

        int i=;

        int sum1=,sum2=;

        int j;

        while(i<s.size())

        {

            j=i-;

             if(s[j]==s[])++sum1;

             if(s[i]==hashmap[s[]]){

                 ++sum2;

                 if(sum1==sum2){

                      if(i==s.size()-)return isValid(s.substr(,s.size()-));

                      if(i==)return isValid(s.substr(,s.size()-));

                      return isValid(s.substr(,i-))&&isValid(s.substr(i+,s.size()--i));

                 }

             }

            i=i+;

        }

        return false;

    }

};