#include <bits/stdc++.h>
using namespace std;
long long sum,n,k,c;
int main()
{
	scanf("%lld%lld",&n,&k);
	sum+=n;
	while(n>=k)
	{
		c=n/k;
		sum+=c;
		n=c;
	}
	printf("%lld",sum);
	return 0;
}