/in/foo.cc: In function 'void solve()':
/in/foo.cc:50:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |             for (int j=4; j<s[i].size(); j++){
      |                           ~^~~~~~~~~~~~
/in/foo.cc:57:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |             for (int j=pos_y; j<s[i].size(); j++){
      |                               ~^~~~~~~~~~~~
/in/foo.cc:96:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   96 |             for (int i=4; i<O.size(); i++){
      |                           ~^~~~~~~~~