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.math.BigDecimal;
import java.math.BigInteger;
import java.util.*;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.zip.Inflater;

public class Main {
    private static AWriter writer = new AWriter(System.out);
    private static AReader reader = new AReader(System.in);
    private static final int INF=0X3F3F3F3F;
    private static int MAXN=6000+5;
    private static int MAXM=4000+5;
    private static int m,n,N,s,t;
    private static int[] dis;
    private static int[] head;
    private static boolean[] vis;
    private static int[] lev;
    private static int tot;
    private static Edge[][] edges;
    static class Edge{
        int flow,cap;
        public Edge() {
            this.flow = 0;
            this.cap = 0;
        }
    }
    private static int dfs(int s,int t,int flow){
        if(s==t)
            return flow;
        int now=flow;
        for(int i=0;i<N;i++){
            if(lev[i]==lev[s]+1&&edges[s][i].cap>edges[s][i].flow){
                int min=Math.min(now,edges[s][i].cap-edges[s][i].flow);
                int nowFlow=dfs(i,t,min);
                edges[s][i].flow+=nowFlow;
                edges[i][s].flow-=nowFlow;
                now-=nowFlow;
            }
            if(now==0)
                break;
        }
        return flow-now;
    }
    private static boolean bfs(int s,int t){
        lev=new int[MAXN];
        Queue<Integer> queue=new LinkedBlockingQueue<>();
        queue.add(s);
        lev[s]=1;
        while(!queue.isEmpty()){
            int u=queue.poll();
            for(int i=0;i<N;i++){
                if(lev[i]==0&&edges[u][i].cap>edges[u][i].flow){
                    lev[i]=lev[u]+1;
                    queue.add(i);
                }
            }
        }
        return lev[t]!=0;
    }
    private static void dinic(int s,int t){
        int flow=0,tf=0;
        while(bfs(s,t)){
            while((tf=dfs(s,t,INF))!=0){
                flow+=tf;
            }
        }
    }
    private static int[][] save;
    public static void main(String[] args) throws IOException {
        n=reader.nextInt();
        writer.println(n%2==0?1<<(n/2):0);
        writer.close();
        reader.close();
    }
}

class AReader implements Closeable {
    private BufferedReader reader;
    private StringTokenizer tokenizer;
    public AReader(InputStream inputStream) {
        reader = new BufferedReader(new InputStreamReader(inputStream));
        tokenizer = new StringTokenizer("");
    }
    private String innerNextLine() {
        try {
            return reader.readLine();
        } catch (IOException ex) {
            return null;
        }
    }
    public boolean hasNext() {
        while (!tokenizer.hasMoreTokens()) {
            String nextLine = innerNextLine();
            if (nextLine == null) {
                return false;
            }
            tokenizer = new StringTokenizer(nextLine);
        }
        return true;
    }
    public String nextLine() {
        tokenizer = new StringTokenizer("");
        return innerNextLine();
    }
    public String next() {
        hasNext();
        return tokenizer.nextToken();
    }
    public int nextInt() {
        return Integer.valueOf(next());
    }
    public long nextLong() {
        return Long.valueOf(next());
    }
    public double nextDouble() {
        return Double.valueOf(next());
    }
    public BigDecimal nextBigDecimal(){ return new BigDecimal(next()); }
    public BigInteger nextBigInteger() {
        return new BigInteger(next());
    }
    @Override
    public void close() throws IOException {
        reader.close();
    }
}

// Fast writer for ACM By Azure99
class AWriter implements Closeable {
    private BufferedWriter writer;

    public AWriter(OutputStream outputStream) {
        writer = new BufferedWriter(new OutputStreamWriter(outputStream));
    }

    public void print(Object object) throws IOException {
        writer.write(object.toString());
    }

    public void println(Object object) throws IOException {
        writer.write(object.toString());
        writer.write("\n");
    }

    @Override
    public void close() throws IOException {
        writer.close();
    }
}

class model{
//    private static void dijkstra(int start){
//        PriorityQueue<Main.Node> queue=new PriorityQueue<>();
//        queue.add(new Main.Node(start,0));
//        dis[start][0]=0;
//        while(!queue.isEmpty()){
//            Main.Node node=queue.poll();
//            int law=node.mes/n;
//            int u=node.mes%n;
//            if(vis[u][law])
//                continue;
//            vis[u][law]=true;
//            for(int i=head[u];i!=-1;i=edges[i].next){
//                int v = edges[i].to;
//                if (dis[v][law] > dis[u][law] + edges[i].w) {
//                    dis[v][law] = dis[u][law] + edges[i].w;
//                    queue.add(new Main.Node(v+law*n,dis[v][law]));
//                }
//                if(law<k&&dis[v][law+1]>dis[u][law]){
//                    dis[v][law+1] = dis[u][law];
//                    queue.add(new Main.Node(v+(law+1)*n,dis[v][law+1]));
//                }
//            }
//        }
//    }
}