foo.c: In function 'main':
foo.c:17:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n1,&n2);
  ^~~~~~~~~~~~~~~~~~~~~
foo.c:18:23: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=0;i<n1;i++)scanf("%d",&a[i]);
                       ^~~~~~~~~~~~~~~~~
foo.c:19:23: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=0;i<n2;i++)scanf("%d",&b[i]);
                       ^~~~~~~~~~~~~~~~~

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