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.StringTokenizer;

public class Solution {
    public static void main(String[] args) {
        try {
            FastScanner in = new FastScanner(System.in);
            PrintWriter out = new PrintWriter(System.out);
            int n = in.nextInt();
            int solution;
            if (n % 2 == 1) solution = 0;
            else solution = 1 << (n / 2);
            out.println(solution);
            out.close();

        } catch(Exception exc) {
            throw new RuntimeException(exc);
        }
    }

    //@
    static class FastScanner {
        BufferedReader br;
        StringTokenizer st;

        public FastScanner(InputStream i) {
            br = new BufferedReader(new InputStreamReader(i));
            st = new StringTokenizer("");
        }

        public String next() throws IOException {
            if(st.hasMoreTokens())
                return st.nextToken();
            else
                st = new StringTokenizer(br.readLine());
            return next();
        }

        public int nextInt() throws IOException {
            return Integer.parseInt(next());
        }
        //#
        public long nextLong() throws IOException {
            return Long.parseLong(next());
        }
        public double nextDouble() throws IOException {
            return Double.parseDouble(next());
        }
        //$
    }
}



