In file included from /usr/include/c++/11/unordered_map:35,
                 from answer.code:2:
/usr/include/c++/11/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
   32 | #error This file requires compiler and library support \
      |  ^~~~~
answer.code:9:1: error: ‘unordered_map’ does not name a type
    9 | unordered_map<string,ll>mp;
      | ^~~~~~~~~~~~~
answer.code: In function ‘int main()’:
answer.code:17:17: error: ‘mp’ was not declared in this scope
   17 |                 mp[s]++;
      |                 ^~
answer.code:23:22: error: ‘mp’ was not declared in this scope
   23 |                 ans+=mp[a]*mp[b];
      |                      ^~