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 test {
	/*
	 * array list
	 * 
	 * ArrayList<Integer> al=new ArrayList<>(); creating BigIntegers
	 * 
	 * BigInteger a=new BigInteger(); BigInteger b=new BigInteger();
	 * 
	 * hash map
	 * 
	 * HashMap<Integer,Integer> hm=new HashMap<Integer,Integer>(); for(int
	 * i=0;i<ar.length;i++) { Integer c=hm.get(ar[i]); if(hm.get(ar[i])==null) {
	 * hm.put(ar[i],1); } else { hm.put(ar[i],++c); } }
	 * 
	 * while loop
	 * 
	 * int t=sc.nextInt(); while(t>0) { t--; }
	 * 
	 * array input
	 * 
	 * int n = sc.nextInt(); int ar[] = new int[n]; for (int i = 0; i < ar.length;
	 * i++) { ar[i] = sc.nextInt(); }
	 */

	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;
		}
	}

	private static final Scanner sc = new Scanner(System.in);
	private static final FastReader fs = new FastReader();

	public static void main(String[] args) {
		int n=sc.nextInt();
		if(n%2!=0)
			System.out.println(0);
		else
		{
			int x=n/2;
			System.out.println((int)Math.pow(2, x));
		}
	}

}/* till here */
