5 3
 1000 3
 777 17
 4 3
 2 2
 100 4
 10 4
 999 2
 6 4
 1 2
 17 3
 1 4
 26 8
 91 5
 1 3
 1000 2
 20 3
 9 4
 123 5
 1000 1000
 3 2
 3 3
 80 970
 1000 4
 1 1000

7
 1499
 825
 5
 3
 133
 13
 1997
 7
 1
 25
 1
 29
 113
 1
 1999
 29
 11
 153
 1001
 5
 4
 80
 1333
 1

#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b, sum = a % b;
  cin >> a >> b;
  while (a >= b) {
    sum += a - a % b;
    a = (a - a % b) / b + a % b;
  }
  cout << sum + a << endl;
  return 0;
}
