foo.cc: In function 'int main()':
foo.cc:6:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    6 |  scanf("%d %d", &E, &n);
      |  ~~~~~^~~~~~~~~~~~~~~~~
foo.cc:10:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   10 |   scanf("%d %d", &a[i], &b[i]);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务