#include <bits/stdc++.h>
using namespace std;
int n,k,sum;
int main(){
	cin>>n>>k;
	sum+=n;
	while(1){
		sum+=n/k;
		n/=k;
		int tmp=n%k;
		n+=tmp;
		if(n<k) break; 
	}
	cout<<sum;
}