/in/foo.cc: In function 'int main()':
/in/foo.cc:36:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 | for(int j=0;j<G[i].size();j++)
      |             ~^~~~~~~~~~~~