foo.cc: In function 'int main()':
foo.cc:11:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 |     scanf("%d%d",&n,&m);
      |     ~~~~~^~~~~~~~~~~~~~
foo.cc:14:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   14 |       scanf("%d",&yao[i][j]);
      |       ~~~~~^~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务