Codeforces_379A

//Codeforces Round 379A
#include <iostream>
using namespace std ;
int main()
{
   int a, b, sum = 0, t = 0, k = 0;
   cin >> a >> b ;
   while(a)
   {
     sum = sum + a;
     a = a + t;
     t = a%b;
     a = a / b;
   }
   cout << sum;
   return 0;
}