foo.c: In function 'Unique':
foo.c:20:1: warning: control reaches end of non-void function [-Wreturn-type]
   20 | }
      | ^
foo.c: In function 'main':
foo.c:24:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   24 |  scanf("%d%d",&n1,&n2);
      |  ^~~~~~~~~~~~~~~~~~~~~
foo.c:26:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   26 |   scanf("%d",&a[i]);
      |   ^~~~~~~~~~~~~~~~~
foo.c:28:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   28 |   scanf("%d",&b[i]);
      |   ^~~~~~~~~~~~~~~~~

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