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

public class Main {
    static int[][] dp;
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        dp = new int[n + 1][n + 1];
        dp[0][0] = 1;
        System.out.println(dfw(n, n));
    }
    
    static int dfw(int left, int right) {
        if (left > right || left < 0) {
            return 0;
        }
        if (dp[left][right] == 0) {
            dp[left][right] = dfw(left - 1, right) + dfw(left, right - 1);
        }
        return dp[left][right];
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    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();
    }
    
}