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.PrintWriter;
import java.lang.reflect.Array;
import java.util.*;
import java.util.Scanner;
public class Solution {
    static Scanner sc = new Scanner(System.in);
    static PrintWriter pw = new PrintWriter(System.out);
    public static void solve(int c, int n){
        int[] dp = new int[n + 1];
        dp[1] = 0;
        if (n >= 2){
            dp[2] = 2;
        }
        for (int i = 3; i <= n; i ++){
            dp[i] = 2 * dp[i - 2];
        }
        System.out.println(dp[n]);
    }

    public static void main(String[] args) {
        int t = 1;
        for (int i = 0; i < t; i ++){
            int n = sc.nextInt();
            solve(i + 1, n);
        }
        pw.close();
    }
}










//    public static void floodfill(char[][] arr, boolean[][] visited, int row, int col){
//        visited[row][col] = true;
//        if (row != 0){
//            if (arr[row - 1][col] == '#' && !visited[row - 1][col]){
//                floodfill(arr, visited, row - 1, col);
//                visited[row - 1][col] = true;
//            }
//        }
//        if (row != arr.length - 1){
//            if (arr[row + 1][col] == '#' && !visited[row + 1][col]){
//                floodfill(arr, visited, row + 1, col);
//                visited[row + 1][col] = true;
//            }
//        }
//        if (col != 0){
//            if (arr[row][col - 1] == '#' && !visited[row][col - 1]){
//                floodfill(arr, visited, row, col - 1);
//                visited[row][col - 1] = true;
//            }
//        }
//        if (col != arr[0].length - 1){
//            if (arr[row][col + 1] == '#' && !visited[row][col + 1]){
//                floodfill(arr, visited, row, col + 1);
//                visited[row][col + 1] = true;
//            }
//        }
//    }
