#include <iostream>
using namespace std;
int main()
{
	int n, k;
	cin>>n>>k;
	while((n!=0) || (k!=0))
	{
		if((n==k) || (k==0))
		    cout<<1<<endl;
		else
		{
			if(k>n/2)
				k=n-k;
			long long int result=1;
			for(int i=1; i<=k; i++)
			{
				result=result*n;
				n--;
				result=result/i;
			}
			cout<<result<<endl;
		}
		cin>>n>>k;
	}
	return 0;
}