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