#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <utility>
#include <string>
#include <queue>
#include <stack>

using namespace std;

typedef long long int ll;
typedef pair<int, int> Pii;

const ll mod = 998244353;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);

  ll h, a;
  cin >> h >> a;

  ll ans = 0;
  ll slime_health = h;
  ll slime_num = 1;
  while (slime_health > 0) {
    ans += slime_num;
    slime_health /= a;
    slime_num *= 2;
  }

  cout << ans << endl;

  return 0;
}