/in/foo.cc: In function 'int main()':
/in/foo.cc:50:7: warning: statement has no effect [-Wunused-value]
  for(w;w<=p[0].first;++w){
       ^
/in/foo.cc:53:7: warning: statement has no effect [-Wunused-value]
  for(w;w<=262144;++w) if(check(w)) cout<<w<<"\n",exit(0);
       ^