#include<iostream>
using namespace std;
int main()
{
	int n, k;
	cin >> n >> k;
	int sum = n, sump = 0, m;
	while (n >= k)
	{
		n = n / k;
		sump = sum - (n * k);
		m = n + sump;
		sum = sum + n;
	}
	cout << sum;
	return 0;
}