/in/foo.cc: In function 'int main()':
/in/foo.cc:61:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 for(int n = 0; n < edge[first].size(); n++){
                                ~~^~~~~~~~~~~~~~~~~~~~
/in/foo.cc:74:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 for(int n = 0; n < edge[first].size(); n++){
                                ~~^~~~~~~~~~~~~~~~~~~~
/in/foo.cc:88:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 for(int n = 0; n < edge[first].size(); n++){
                                ~~^~~~~~~~~~~~~~~~~~~~
/in/foo.cc:102:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
                 for(int n = 0; n < edge[first].size(); n++){
                                ~~^~~~~~~~~~~~~~~~~~~~
/in/foo.cc:133:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i = 0; i < edge[now].size(); i++){
                        ~~^~~~~~~~~~~~~~~~~~
/in/foo.cc:144:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i = 1; i < ans.size(); i++)
                    ~~^~~~~~~~~~~~