求问大佬如何解决从“double”转换到“int”，可能丢失数据的警告QAQ

#include<iostream>
using namespace std;
int main()
{
   int h, r;
   cin >> h >> r;
   double v = h*3.14*r*r;
   double sum = 20 * 1000;
   int num = ceil(sum / v);
   cout << num;
   system("pause");
   return 0;  
}