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

int main(){
    ll h,a;
    cin >> h >> a;
    ll check=a;
    ll t=1;
    ll su = 1;
    while(check<=h){
        check*=a;
        su += t+1;
        t++;
    }
    cout << su << endl;
}