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.*;
import java.util.*;


public class Solution {
    public static void main (String[] args) throws java.lang.Exception
	{
        FastReader fr = new FastReader();
        int n = fr.nextInt();
        int arr[] = new int[n+1];
        if(n == 1){
            System.out.println(0);
        }
        else{
            arr[1] = 0;
            arr[2] = 2;
            for(int i=3;i<=n;i++){
                arr[i] = arr[i-2]*arr[2];
            }
            System.out.println(arr[n]);
        }

	}
    

    static int gcd(int a, int b) {
      if (b == 0) 
        return a; 
      return gcd(b, a % b);  
    } 
 
    static int lcm(int a, int b){
        int g = gcd(a,b);
        return a*(b/g);
    }
 
    static int exponentMod(int A,  int B, int C)  {    
        if (A == 0)  
            return 0;  
        if (B == 0)  
            return 1;    
        long y;  
        if (B % 2 == 0) 
        {  
            y = exponentMod(A, B / 2, C);  
            y = (y * y) % C;  
        }    
        else 
        {  
            y = A % C;  
            y = (y * exponentMod(A, B - 1,  C) % C) % C;  
        }  
        return (int)((y + C) % C);  
    }
 
    static class FastReader{ 
        BufferedReader br; 
        StringTokenizer st; 
 
        public FastReader() 
        { 
            br = new BufferedReader(new
                     InputStreamReader(System.in)); 
        } 
 
        String next() 
        { 
            while (st == null || !st.hasMoreElements()) 
            { 
                try
                { 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
 
        int nextInt() 
        { 
            return Integer.parseInt(next()); 
        } 
 
        long nextLong() 
        { 
            return Long.parseLong(next()); 
        } 
 
        double nextDouble() 
        { 
            return Double.parseDouble(next()); 
        } 
 
        String nextLine() 
        { 
            String str = ""; 
            try
            { 
                str = br.readLine(); 
            } 
            catch (IOException e) 
            { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    }    
}