foo.cc: In function 'int main()':
foo.cc:11:7: 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:21:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   21 |   scanf("%d%d",&x,&y);
      |   ~~~~~^~~~~~~~~~~~~~
foo.cc:22:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   22 |   scanf("%d",&mp[x][y]);
      |   ~~~~~^~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务