answer.code:8:1: error: ‘unordered_map’ does not name a type
    8 | unordered_map<string,ll>mp;
      | ^~~~~~~~~~~~~
answer.code: In function ‘int main()’:
answer.code:16:17: error: ‘mp’ was not declared in this scope
   16 |                 mp[s]++;
      |                 ^~
answer.code:22:22: error: ‘mp’ was not declared in this scope
   22 |                 ans+=mp[a]*mp[b];
      |                      ^~