/in/foo.cc: In function 'void dfs(int)':
/in/foo.cc:8:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<e[p].size();++i){
              ~^~~~~~~~~~~~
/in/foo.cc: In function 'int find(int)':
/in/foo.cc:40:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<e[x].size();++i){
               ~^~~~~~~~~~~~