/* Header:
   Program to calculate the Nth Catalan Number
*/

import java.util.Scanner;

public class CatalanNumber {

    // Recursive function to find Catalan number
    public static int catalan(int n) {
        if (n <= 1)  // Base case: C(0) = 1, C(1) = 1
            return 1;

        int result = 0;

        // Apply Catalan formula: C(n) = Σ C(i) * C(n-i-1)
        for (int i = 0; i < n; i++) {
            result += catalan(i) * catalan(n - i - 1);
        }

        return result;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        // Input validation
        if (!sc.hasNextInt()) {
            System.out.println("Invalid input");
            return;
        }

        int n = sc.nextInt();

        if (n < 0 || n > 15) {  // Check range
            System.out.println("Invalid input");
        } else {
            System.out.println(catalan(n));
        }

        sc.close();
    }
}

/* Footer:
   End of Program
*/