#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;
int main()
{
	int y,d=0,k,z=0;
	cin>>y>>k;
	while(y!=0)
	{
		d=d+y;	
		z=d+z;
	    y=d/k;
		d=0;
	}
	cout<<z;
	return 0;
}