#include <bits/stdc++.h>
using namespace std;

long long powll(long long x, long long n) {
  long long ret = 1;

  while (n > 0) {
    if (n & 1) ret *= x;
    x *= x;
    n >>= 1;
  }

  return ret;
}

int main() {
  long long h, a;
  cin >> h >> a;
  long long count = 0;
  while (h > 0) {
    count++;
    h /= a;
  }
  cout << powll(2LL, count) - 1 << '\n';
  return 0;
}