/in/foo.cc: In function 'void dfs(int)':
/in/foo.cc:26:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<connections[u].size(); ++i)
                  ~^~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:55:13: error: expected ';' before '{' token
             {
             ^