foo.c:37:6: warning: return type of 'main' is not 'int' [-Wmain]
   37 | void main()
      |      ^~~~
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 %d %d ",&n1,&n2,&n3);
      |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.c:43:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   43 |  scanf("%d",&a1[b]);
      |  ^~~~~~~~~~~~~~~~~~
foo.c:45:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   45 |  scanf("%d",&a2[b]);
      |  ^~~~~~~~~~~~~~~~~~
foo.c:47:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   47 |  scanf("%d",&a3[b]);
      |  ^~~~~~~~~~~~~~~~~~

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