/in/foo.cc: In member function 'void data::get(int, int)':
/in/foo.cc:68:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int j=0;j<st[i].size();j++)
                 ~^~~~~~~~~~~~~
/in/foo.cc: In member function 'void data::solve(int)':
/in/foo.cc:80:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<a[x].size();i++)
               ~^~~~~~~~~~~~
/in/foo.cc:86:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<V.size();i++)vis[V[i]]=0;
               ~^~~~~~~~~
/in/foo.cc:87:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<M.size();i++)mark[M[i]]=0;
               ~^~~~~~~~~