foo.cc: In function 'int main()':
foo.cc:10:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   10 |  scanf("%d/%d",&a1,&b1);
      |  ~~~~~^~~~~~~~~~~~~~~~~
foo.cc:11:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 |  scanf("%d/%d",&a2,&b2);
      |  ~~~~~^~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务