/in/foo.cc: In function 'int main()':
/in/foo.cc:10:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<v.size();i++)
              ~^~~~~~~~~
/in/foo.cc:12:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0;j<v[i].size();j++)
               ~^~~~~~~~~~~~
/in/foo.cc:18:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(v[i].size()>maxn)maxn=v[i].size();
      ~~~~~~~~~~~^~~~~
/in/foo.cc:20:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<v.size();i++)
              ~^~~~~~~~~
/in/foo.cc:21:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(v[i].size()==maxn)
      ~~~~~~~~~~~^~~~~~