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.util.Scanner;

public class CodeForces{

    public static void main(String[] args){
        Scanner s = new Scanner(System.in);
        int n = s.nextInt();

        int[] dyn = new int[n+1];
        if(n>2){
            dyn[0]=0;
            dyn[1]=0;
            dyn[2]=2;
            for(int i=3; i<dyn.length; i++){
                if(i%2==0){
                    int max = 0;
                    for(int j=0; j<i; j++){
                        if(dyn[j]>max){
                            max = dyn[j];
                        }
                    }
                    dyn[i] = max*2;
                }
                else{
                    dyn[i] = 0;
                }
            }
        }
        else{
            if(n==0){
                dyn[0]=0;
            }
            else if(n==2){
                dyn[2]=2;
            }
            else{
                dyn[1]=0;
            }
        }
        System.out.print(dyn[n]);
    }

}