foo.c: In function 'Merge':
foo.c:34:1: warning: control reaches end of non-void function [-Wreturn-type]
   34 | }
      | ^
foo.c: In function 'main':
foo.c:40:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   40 |  scanf("%d",&n1);
      |  ^~~~~~~~~~~~~~~
foo.c:41:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   41 |  scanf("%d",&n2);
      |  ^~~~~~~~~~~~~~~
foo.c:42:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   42 |  scanf("%d",&n3);
      |  ^~~~~~~~~~~~~~~
foo.c:45:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   45 |  scanf("%d",&a1[i]);
      |  ^~~~~~~~~~~~~~~~~~
foo.c:47:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   47 |  scanf("%d",&a2[i]);
      |  ^~~~~~~~~~~~~~~~~~
foo.c:49:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   49 |  scanf("%d",&a3[i]);
      |  ^~~~~~~~~~~~~~~~~~

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