#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using i64 = long long int;
int main() {
  i64 h, a;
  cin >> h >> a;
  int phase = 0;
  while (h >= 1) {
    h /= a;
    phase++;
  }
  cout << ((1LL << phase) - 1) << "\n";
  return 0;
}