/in/foo.cc: In function 'int query(int, int)':
/in/foo.cc:62:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(t-k>=down[y].size()){puts("WA");exit(0);}
      ~~~^~~~~~~~~~~~~~~~
/in/foo.cc:65:8: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if(k-t>=up[y].size()){puts("WA");exit(0);}
     ~~~^~~~~~~~~~~~~~