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 Main {
  static InputStream inputStream = System.in;
  static OutputStream outputStream = System.out;
  static InputReader in = new InputReader(inputStream);
  static PrintWriter out = new PrintWriter(outputStream);

  static long power (long base, int k) {
    if (k == 0) return 1;
    return base * power(base, k - 1);
  }
  
  public static void main(String[] args) {
    int n = in.nextInt();

    if (n > 1 && n % 2 == 0) {
      out.println(power((long)2, (n / 2)));
    } else {
      out.println(0);
    }

    out.close();
  }

  static class InputReader {
    public BufferedReader reader;
    public StringTokenizer tokenizer;

    public InputReader(InputStream stream) {
      reader = new BufferedReader(new InputStreamReader(stream), 32768);
      tokenizer = null;
    }

    public String next() {
      while (tokenizer == null || !tokenizer.hasMoreTokens()) {
        try {
          tokenizer = new StringTokenizer(reader.readLine());
        } catch (IOException e) {
          throw new RuntimeException(e);
        }
      }
      return tokenizer.nextToken();
    }

    public int nextInt() {
      return Integer.parseInt(next());
    }

    public long nextLong () {
      return Long.parseLong(next());
    }

    public char nextChar () {
      return next().charAt(0);
    }
  }
}