public class WS1617Rekursion {
	public static int f(int n) {
		int prod = 1;
		while (n > 1) {
			prod = prod * n;
			n = n - 2;
		}
		return prod;
	}

	public static int fRec(int n) {
		if (n <= 1)
			return 1;
		return n * fRec(n-2);
	}
}