#include <iostream>
#include <string>
using ll = long long;
using llu = long long unsigned;

using namespace std;

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

    ll result = 0;
    ll count = 1;
    while (H > 0) {
        H /= A;
        result += count;
        count *= 2;
    }
    cout << result << endl;
    return 0;
}