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

int main()
{
    long long H, A;
    cin >> H >> A;
    int count = 0;
    while (H)
    {
        H /= A;
        count++;
    }
    long long ans = 1;
    for (int i = 1; i <= count ; i++)
    {
        ans *= 2;
    }
    ans -= 1;
    cout << ans;
}