#include <iostream>
using namespace std;

void smoke(int &tobacco, int &cb, int k) {
	int new_tobacco = cb / k;
	int new_cb = new_tobacco;
	int tobacco_sum = tobacco + new_tobacco;
	tobacco = tobacco_sum;
	cb = new_cb;

}

int main() {
	int n, k;

	cin >> n >> k;
	int cb = n;
	while (cb > 0) {
		smoke(n, cb, k);

	}
	cout <<n;


	return 0;
}

cb是烟蒂 求助第三个WA了