#include<stdio.h>

void main( )
{
	long n,k,s,r;
	while(scanf("%ld%ld",&n,&k)!=EOF)
	{
		s=n;
		r=n/k;
		while(r>0)
		{	
			s+=r;
			r/=k;
		}
		printf("%ld\n",s);
	}
}