Segitiga Ajaib

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

public class Solution {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt(), x = 1;
        for (int i = 1; i < N; i++) x *= 2;
        System.out.println(x/N);
    }
}