/in/foo.cc: In function 'int main()':
/in/foo.cc:74:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    while(f[i].size() < K){
          ~~~~~~~~~~~~^~~
/in/foo.cc:85:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if(f[370].size() < K) return printf("-1"), 0;
     ~~~~~~~~~~~~~~^~~
/in/foo.cc:42:6: warning: unused variable 'islp' [-Wunused-variable]
  int islp = 0;
      ^~~~