#include<iostream>
using namespace std;
int main()
{
	long long n,k,sum=0,num=0;
	cin>>n>>k;
	sum+=n;
	num+=n; 
	while(1)
	{
		if(num/k>0)
		{
			sum+=num/k;
			num=num/k;
		}
		else
		{
			break;
		}
	}
	cout<<sum;
	return 0;
}