答案

#include <iostream> 
#include <cmath>  
using namespace std; 
int main() { 
    
   const double NEED_WATER = 20000.0;  
   const double PI = 3.14;  
   int h, r; 
   cin >> h >> r; 
   double bucket_volume = PI * r * r * h; 
   int buckets = ceil(NEED_WATER / bucket_volume); 
   cout << buckets << endl; 

   return 0; 
}