foo.c: In function 'main':
foo.c:16:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf ("%d",&n);
  ^~~~~~~~~~~~~~~
foo.c:20:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   scanf ("%d",&j);
   ^~~~~~~~~~~~~~~
foo.c:23:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf ("%d",&k);
  ^~~~~~~~~~~~~~~

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