#include<bits/stdc++.h>

using namespace std;

int main() {
    int n, k;
    cin >> n >> k;
    int ans = 0;
    int num = 0;
    while (n > 0) {
        ans += n;
        int x = n + num;
        num = x % k;
        n = x / k;
    }
    cout << ans << endl;
    return 0;
}