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.*;
import java.math.*;
import java.io.*;

public class B{
	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; 
	    } 
	}

	public static void main(String[] args){
		FastReader in = new FastReader(); 
		// int t = in.nextInt();
		// while(t-- != 0){
			int n = in.nextInt();
			if(n % 2 == 1){ System.out.println("0"); }
			else{ System.out.println((int)Math.pow(2, n / 2)); }
			// long res = 0;
			// for(int i = 0; i < n; i++){
			// 	int a = in.nextInt();
			// 	if(a == 0) zero++;
			// 	if(a >= 0){
			// 		res += Math.abs(a - 1);
			// 	}else{
			// 		res += Math.abs((-1) - a);
			// 		neg++;
			// 	}
			// }
			
		// }
	}

}


