/in/foo.cc: In function 'int main()':
/in/foo.cc:47:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j=0;j<ans[i].size();++j){
                     ~^~~~~~~~~~~~~~
/in/foo.cc:74:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int j=0;j<bns[i].size();++j){
                     ~^~~~~~~~~~~~~~