//No.40 多項式の割り算

import java.util.*;
import java.io.*;
import static java.util.Arrays.*;
import static java.lang.Math.*;

public class No40 {
    
    static final Scanner sc = new Scanner(System.in);
    static final PrintWriter out = new PrintWriter(System.out,false);

    static void solve() {
        int d = sc.nextInt();
        int[] a = new int[d+1];
        for (int i=0; i<=d; i++) {
            a[i] = sc.nextInt();
        }

        for (int i=d; i>=3; i--) {
            a[i-2] += a[i];
            a[i] = 0;
        }
        int dim = 0;
        for (int i=0; i<min(3,d+1); i++) {
            if (a[i] != 0) dim = i;
        }
        out.println(dim);
        for (int i=0; i<=dim; i++) {
            if (i != dim) out.print(a[i]+" ");
            else out.println(a[i]);
        }
    }

    public static void main(String[] args) {
        long start = System.currentTimeMillis();

        solve();
        out.flush();

        long end = System.currentTimeMillis();
        //trace(end-start + "ms");
        sc.close();
    }

    static void trace(Object... o) { System.out.println(deepToString(o));}
}