import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		sc.close();
		long ans = comb(2 * N, N) / (N + 1);
		System.out.println(ans);
	}
	static long comb(int n, int k) {
        if(n < k) {
            int t = n;
            n = k;
            k = t;
        }
        if(k == 0) {
            return 1;
        }else if(n == k) {
            return 1;
        }else {
            return comb(n - 1, k - 1) * n / k;
        }
    }
}