#include<stdio.h>
int main()
{
	double n,k,i,j,sum;
	while(scanf("%lf%lf",&n,&k))
	{
		if(n==0&&k==0)
			break;
		sum=1;
		for(i=n,j=1;j<=k;i--,j++)
		{
			sum=sum*1.0/j*1.0*i*1.0;
		}
		printf("%.0lf\n",sum);
	}return 0;
}