/in/foo.cc: In function 'int main()':
/in/foo.cc:14:14: error: 'cout' is not a member of 'std'
   14 |         std::cout << ans << std::endl;
      |              ^~~~
/in/foo.cc:3:1: note: 'std::cout' is defined in header '<iostream>'; did you forget to '#include <iostream>'?
    2 | #include <cmath>
  +++ |+#include <iostream>
    3 | 
/in/foo.cc:14:34: error: 'endl' is not a member of 'std'
   14 |         std::cout << ans << std::endl;
      |                                  ^~~~
/in/foo.cc:3:1: note: 'std::endl' is defined in header '<ostream>'; did you forget to '#include <ostream>'?
    2 | #include <cmath>
  +++ |+#include <ostream>
    3 |