foo.c:3:6: warning: return type of 'main' is not 'int' [-Wmain]
    3 | void main()
      |      ^~~~
foo.c: In function 'main':
foo.c:7:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    7 |  scanf("%d %d",&n1,&n2);
      |  ^~~~~~~~~~~~~~~~~~~~~~
foo.c:9:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
    9 |   scanf("%d",&a[i]);
      |   ^~~~~~~~~~~~~~~~~
foo.c:11:3: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   11 |   scanf("%d",&b[i]);
      |   ^~~~~~~~~~~~~~~~~

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