using namespace std;

int main() {
	long num, n, k, d, l;
	cin >> n >> k;
	num = n;
	l = 0;
	while (d - k > 0) {
		d = n + l;
		n = d / k;
		l = d % k;
		num+= n;
	}
	cout << num << endl;
	return 0;
}