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

int main() {
    ll h, a;
    cin >> h >> a;
    int count=0;
    while(h>0) {
        h=h/a;
        count++;
    }
    ll ans=0;
    for(ll i=0; i<count; i++) {
        ans+=pow(2, i);
    }
    cout << ans << endl;
}