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 = 0, w = 0, coun1 = 0, m = 0, y = 0;
  cin >> a >> b;
  if (a < b)
    cout << a;
  else if (a - b == 1)
    cout << a + b;
  else {
    w = a;
    for (int i = 0; i < a; i++) {
      w = w / b;
      coun1 = coun1 + w;
      if (w % b != 0) {
        m++;
      }
      if (coun1 >= a - 1) break;
    }
    if (m > 1)
      m = m;
    else if (m <= 1)
      m = m - 1;
    if (coun1 + m == a) coun1 = coun1 - 1;
    cout << a + coun1 + m;
  }
  return 0;
}
