#include<iostream>
#include<cstdio>
using namespace std;
int main()
{
	int n=0,k=0;
	scanf("%d%d",&n,&k);
	int sum=n;
	int jishu,ss,jishu1=n/k;
	sum=sum+jishu1;
	ss=n%k;
	jishu=jishu1+ss;
	while(jishu>=k)
	{
        jishu=jishu/k;
		sum=sum+jishu;
		jishu=jishu+(jishu%k);
        
	}
	printf("%d",sum);
	return 0;
}