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>
int a, b;
int old;
int leftold;
int hours;
int main() {
  scanf("%d %d", &a, &b);
  hours = a;
  old = a / b;
  leftold = a % b;
  for (int i = 0; i < 2; ++i) {
    while (old > 0) {
      hours += old;
      leftold += old % b;
      old /= b;
    }
    old = leftold / b;
  }
  printf("%d\n", hours);
  return 0;
}
