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 hack{

  public 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();
        }

        String [] nextArray(){
            StringTokenizer tokens = new StringTokenizer(nextLine(), " ");
            String[] splited = new String[tokens.countTokens()];
            int index = 0;
            while(tokens.hasMoreTokens()){
              splited[index] = tokens.nextToken();
              if(splited[index]!="")
                ++index;
            }
            return splited;
        }

        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[]) throws IOException{
       //Reader in = new Reader();
       FastReader in=new FastReader();
       BufferedOutputStream out=new BufferedOutputStream(System.out);
       StringBuilder sb = new StringBuilder();

       int i,j;
       int n=in.nextInt();
       int k=n/2;
       long ans=0;
       if(n%2==0)
        ans=(long)Math.pow(2l,k);
       sb.append(ans);
       //System.out.println(flag+" "+k1+" "+k2+" "+count+" "+c);
       out.write(sb.toString().getBytes());
       out.flush();
    }


}
