/in/foo.cc: In function 'int getans(int, int)':
/in/foo.cc:91:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if (V[x].size()<=(1<<L)-y) return 0;
      ~~~~~~~~~~~^~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:107:6: warning: unused variable 'm' [-Wunused-variable]
  int m=read();
      ^