answer.code: In function ‘int main()’:
answer.code:6:1: error: ‘cin’ was not declared in this scope; did you mean ‘std::cin’?
    6 | cin >> n >> m;
      | ^~~
      | std::cin
In file included from answer.code:2:
/usr/include/c++/13/iostream:62:18: note: ‘std::cin’ declared here
   62 |   extern istream cin;           ///< Linked to standard input
      |                  ^~~
answer.code:7:1: error: ‘cout’ was not declared in this scope; did you mean ‘std::cout’?
    7 | cout << 6LL * n * m;
      | ^~~~
      | std::cout
/usr/include/c++/13/iostream:63:18: note: ‘std::cout’ declared here
   63 |   extern ostream cout;          ///< Linked to standard output
      |                  ^~~~