#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <cstring>
#include <string>
#include <algorithm>
#include <cmath>
#include <vector>
#include <queue>
#include <stack>
#include <deque>
#include <map>
#include <unordered_map>
#include <set>
#include <unordered_set>
#include <functional>

typedef long long int ll;
using namespace std;
#define INF 1234567890
#define N 200000

const int LIMIT = 1e+9;
int n, m;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	while (true) {
		long long res = 1;
		cin >> n >> m;
		if (n == 0 && m == 0)
			break;
		m = min(m, n - m);

		for (int i = 1; i <= m; i++) {
			res *= n;
			res /= i;
			n--;
		}
		cout << res << "\n";
	}

	return 0;
}