/in/foo.cc: In function 'int main()':
/in/foo.cc:13:9: error: 'cout' was not declared in this scope
   13 |         cout << ans << endl;
      |         ^~~~
/in/foo.cc:13:24: error: 'endl' was not declared in this scope
   13 |         cout << ans << endl;
      |                        ^~~~