import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        long[][] dp = new long[n * 2 + 1][n + 1];
        dp[0][0] = 1;
        for (int i = 0; i < 2 * n; i++) {
            dp[i + 1][1] += dp[i][0];
            dp[i + 1][n - 1] += dp[i][n];
            for (int j = 1; j < n; j++) {
                dp[i + 1][j + 1] += dp[i][j];
                dp[i + 1][j - 1] += dp[i][j];
            }
        }
        System.out.println(dp[n * 2][0]);
    }
}

class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public double nextDouble() throws Exception {
        return Double.parseDouble(next());
    }
    
    public String next() throws Exception {
        while (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}