import java.util.*;

public class Main {
    static long[][] dp;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        dp = new long[n + 1][n + 1];
        dp[0][0] = 1;
        System.out.println(dfw(n , n));
    }
    
    static long dfw(int open, int close) {
        if (open < 0 || close < 0) {
            return 0;
        }
        if (open < close) {
            return 0;
        }
        if (dp[open][close] != 0) {
            return dp[open][close];
        }
        dp[open][close] = dfw(open - 1, close) + dfw(open, close - 1);
        return dp[open][close];
    }
}