/in/foo.cc: In function 'void dfs(int, int)':
/in/foo.cc:30:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 for(int i=0;i<g[u].size();i++){
             ~^~~~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:85:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 for(int j=0;j<g[ord[i]].size();j++)
             ~^~~~~~~~~~~~~~~~~