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 %d",&n1,&n2);
      |  ^~~~~~~~~~~~~~~~~~~~~~
foo.c:22:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   22 |    scanf("%d",&a[i]);
      |    ^~~~~~~~~~~~~~~~~
foo.c:24:4: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   24 |    scanf("%d",&b[i]);
      |    ^~~~~~~~~~~~~~~~~

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