foo.c: In function 'main':
foo.c:8:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    8 |  scanf("%d", &n);
      |  ^~~~~~~~~~~~~~~
foo.c:9:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    9 |  scanf("%d", &m);
      |  ^~~~~~~~~~~~~~~
foo.c:12:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   12 |   scanf("%d", &a[i]);
      |   ^~~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务