You have a given integer n. Find the number of ways to fill all 3 × n tiles with the shape described in the picture below. Upon filling, no empty spaces are allowed. Shapes cannot overlap.

<image> This picture describes when n = 4. The left one is the shape and the right one is 3 × n tiles. 

Input

The only line contains one integer n (1 ≤ n ≤ 60) — the length.

Output

Print the number of ways to fill.

Examples

Input


4


Output


4

Input


1


Output


0

Note

In the first example, there are 4 possible cases of filling.

In the second example, you cannot fill the shapes in 3 × 1 tiles.
import java.io.IOException;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.*;


public class Main {

    void solve(Scanner in, PrintWriter out) {
        int n = in.nextInt();


        if (n % 2 == 1) {
            out.println(0);
        } else {
            out.println((int)
                    Math.pow(2, n/2));
        }
    }



    public int fact(int n) {
        int result = 1;

        for (int i = 1; i <= n; i++) {
            result *= i;
        }

        return result;

    }


    void run() {
        try (
                Scanner in = new Scanner(System.in);
                PrintWriter out = new PrintWriter(System.out)) {

            solve(in, out);
        }
    }


    public static void main(String[] args) throws IOException {
        new Main().run();
    }


}









