foo.c: In function 'main':
foo.c:20:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   20 |  scanf("%d",&n);
      |  ^~~~~~~~~~~~~~
foo.c:23:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   23 |   scanf("%d",&r);
      |   ^~~~~~~~~~~~~~
foo.c:26:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   26 |  scanf("%d",&v);
      |  ^~~~~~~~~~~~~~

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