#include <iostream>
using namespace std;
int main(){
	int n,k;
	cin>>n>>k;
	int tmp=n;
	int js=n;
	while(tmp>k){
		js+=int(tmp/k);
		tmp=tmp%k+tmp/k;
	}
	cout<<js<<endl;
	return 0;
}

/* 4%3=1   5%3=2 2+int(5/3)=3 3%3=0
	6%4=2 2+6/4=3*/