foo.c: In function 'Output':
foo.c:7:1: warning: control reaches end of non-void function [-Wreturn-type]
    7 | }
      | ^
foo.c: In function 'Merge':
foo.c:25:1: warning: control reaches end of non-void function [-Wreturn-type]
   25 | }
      | ^
foo.c: In function 'main':
foo.c:29:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   29 |  scanf("%d %d %d",&n1,&n2,&n3);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.c:31:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   31 |   scanf("%d",&a1[i]);
      |   ^~~~~~~~~~~~~~~~~~
foo.c:33:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   33 |   scanf("%d",&a2[i]);
      |   ^~~~~~~~~~~~~~~~~~
foo.c:35:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   35 |   scanf("%d",&a3[i]);
      |   ^~~~~~~~~~~~~~~~~~

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