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%d",&n,&m);
      |  ^~~~~~~~~~~~~~~~~~~
foo.c:17:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   17 |    scanf("\n%c",&zhiling);
      |    ^~~~~~~~~~~~~~~~~~~~~~
foo.c:20:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   20 |    scanf("%d%d",&a,&b);
      |    ^~~~~~~~~~~~~~~~~~~
foo.c:39:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   39 |    scanf("%d",&a);
      |    ^~~~~~~~~~~~~~

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