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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class FillingShapes {

	int n;
	long nways;

	private void readData(BufferedReader bin) throws IOException {
		String sss = bin.readLine();
		String []ss = sss.split(" ");
		n = Integer.parseInt(ss[0]);
	}

	void printRes() {
		System.out.println(nways);
	}

	private void calculate() {
		if (n%2 == 1) {
			nways = 0;
			return;
		}
		n = n/2;
		for (nways = 1; n>0; n--) {
			nways = 2*nways; 
		}
	}

	public static void main(String[] args) throws IOException {
		// BufferedReader bin = new BufferedReader(new FileReader("cactus.in"));
		BufferedReader bin = new BufferedReader(new InputStreamReader(System.in));
		FillingShapes l = new FillingShapes();
		l.readData(bin);
		l.calculate();
		l.printRes();
	}
}
