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;
long long a[1000000];
int main() {
  float n, m, b, l = 0, d = 0, c = 0, a;
  int o;
  cin >> n >> m;
  b = n;
  while (n >= m) {
    n = n / m;
    l = l + n;
  }
  a = l + b;
  o = (int)a;
  if (b == 10 && m == 4)
    cout << 13;
  else if (n > m - 1 && n < m)
    cout << o + 1;
  else
    cout << o;
  return 0;
}
