public class BinomialCoefRec {

	private static long C(long n, long k) {
		if ((k == 0) || (n == k))
			return 1;
		return C(n - 1, k) + C(n - 1, k - 1);
	}

	public static void main(String[] args) {
		long n, k, rez;
		long startTime, endTime, duration;
		for (n = 20; n < 50; n++) {
			k = n / 2;
			System.out.print("Starting to work at C(" + n + "," + k + ") ... ");
			startTime = System.nanoTime();
			rez = C(n, k);
			endTime = System.nanoTime();
			duration = (endTime - startTime);
			System.out.println("Done in " + duration / 1000000 + " milisec");
		}
	}
}