#include <stdio.h>
int main()
{
	int have=0;
	int change=0;
	int total=0;
	int b=0;
	scanf("%d %d",&have,&change);
	int c=have;
    do{
    	have=have/change;
    	b+=have;
	}while(have>0);
	total=b+c;
	printf("%d",total);
	return 0;
}