/in/foo.cc: In function 'void init(int, int)':
/in/foo.cc:11:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<a[u].size(); i++)
                  ~^~~~~~~~~~~~
/in/foo.cc: In function 'int work(int, int)':
/in/foo.cc:19:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<a[u].size(); i++)
                  ~^~~~~~~~~~~~
/in/foo.cc: In function 'void dfs(int)':
/in/foo.cc:27:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<d[dep].size(); i++)
                  ~^~~~~~~~~~~~~~