foo.c: In function 'Second1':
foo.c:24:1: warning: control reaches end of non-void function [-Wreturn-type]
   24 | }
      | ^
foo.c: In function 'main':
foo.c:31:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   31 |  scanf("%d%d",&a1,&b1);
      |  ^~~~~~~~~~~~~~~~~~~~~
foo.c:33:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   33 |  scanf("%d",a+i);
      |  ^~~~~~~~~~~~~~~
foo.c:35:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
   35 |  scanf("%d",b+i);
      |  ^~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务