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.
/**
 * _1182A
 */
import java.util.*;
public class _1182A {

    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        long dp[]=new long[n+1];
        if(n>1){
        dp[1]=0; dp[2]=2;}
        System.out.println(countDP(n,dp));

    }
    public static long countDP(int n,long[] dp) {
        if(n==1)
            return 0;
        if(dp[n]!=0)
            return dp[n];
        dp[n]=2*countDP(n-2, dp);
        return dp[n];
    }
}