/in/foo.cc: In function 'void cut(int)':
/in/foo.cc:30:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<tre[x].size();i++)
                 ~^~~~~~~~~~~~~~
/in/foo.cc: In function 'void uncut(int)':
/in/foo.cc:39:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<tre[x].size();i++)
                 ~^~~~~~~~~~~~~~
/in/foo.cc: In function 'int count(int, int)':
/in/foo.cc:50:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<tre[x].size();i++)
                 ~^~~~~~~~~~~~~~
/in/foo.cc: In function 'void dfs(int, int)':
/in/foo.cc:59:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<son[x+1].size();i++)
                 ~^~~~~~~~~~~~~~~~