/* -*- coding: utf-8 -*-
 *
 * 2416.cc:  No.2416 vs Slime - yukicoder
 */

#include<cstdio>
#include<algorithm>
 
using namespace std;

/* constant */

/* typedef */

typedef long long ll;

/* global variables */

/* subroutines */

/* main */

int main() {
  ll h, a;
  scanf("%lld%lld", &h, &a);

  ll y = 0;
  for (ll x = h; x > 0; x /= a) y = 1 + 2 * y;
  printf("%lld\n", y);

  return 0;
}