/in/foo.cc: In function 'void solve()':
/in/foo.cc:224:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < odr1.size(); i++) {
                  ~~^~~~~~~~~~~~~
/in/foo.cc:240:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (int k = 0; k < G[x].size(); k++) {
                    ~~^~~~~~~~~~~~~
/in/foo.cc:229:6: warning: unused variable 'M' [-Wunused-variable]
  int M = m;
      ^