#include <cstdio>
using namespace std;
int main(){
	int n1,k,n2=1,s=0;
	scanf("%d%d",&n1,&k);
	s+=n1;
	while(n2){
		n2=n1/k;
		s+=n2;
		n1=n2;
	}
	printf("%d",s);
	return 0;
}

咋我错了呢，样例全对，第三题wa！！！