#include <bits/stdc++.h>

using namespace std;
using llong = long long;
using ldbl = long double;
using lpair = pair<llong, llong>;

#define ALL(x) x.begin(), x.end()

constexpr llong mod = 1e9+7;
constexpr llong inf = mod * mod;

int main() {
  llong H, A;
  cin >> H >> A;

  llong ans = 0;
  llong cnt = 1;
  while (H) {
    cerr << H << " " << ans << " " << cnt << endl;
    H /= A;
    ans += cnt;
    cnt *= 2;
  }

  cout << ans << endl;

  return 0;
}