foo.cc: In function 'int main()':
foo.cc:34:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   34 |     scanf("%d %d\n", &C, &R);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc:39:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   39 |             scanf("%c", &ch);
      |             ~~~~~^~~~~~~~~~~
foo.cc:43:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   43 |         scanf("%c", &line);
      |         ~~~~~^~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务