#include<bits/stdc++.h>
using namespace std;
using ll = long long;
int main(){
	ll H,A; cin >> H >> A;
	ll ans = 0;
	ll slimes = 1;
	while(H > 0){
		ans += slimes;
		slimes *= 2;
		H /= A;
	}
	cout << ans << endl;
}