#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,k,can=0,x=0;
	cin>>n>>k;
	can+=n;
	while(1){
		x+=n%k;
		n/=k;
		can+=n;
		if(x>=k){
			can+=x/k;
			x-=k;
		}
		if(n/k<=0)
			break;
	}
	cout<<can;
	return 0;
}