foo.cc: In function 'int main()':
foo.cc:9:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    9 |  scanf("%d%d%d",&K,&V,&n);
      |  ~~~~~^~~~~~~~~~~~~~~~~~~
foo.cc:11:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   11 |   scanf("%d%d",&v[i],&w[i]);
      |   ~~~~~^~~~~~~~~~~~~~~~~~~~

[Hydro](https://hydro.ac)提供评测服务