foo.cc: In function 'int main()':
foo.cc:26:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&n1,&n2);
  ~~~~~^~~~~~~~~~~~~~~~~
foo.cc:28:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a1[i]);
   ~~~~~^~~~~~~~~~~~~
foo.cc:30:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&a2[i]);
   ~~~~~^~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务