using System;

public class Hello
{
    static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        string[] line = Console.ReadLine().Trim().Split(' ');
        var a = Array.ConvertAll(line, int.Parse);
        getAns(n, a);
    }
    static void getAns(int n, int[] a)
    {
        n++;
        Array.Reverse(a);
        var t = new int[4];
        for (int i = 0; i < 4; i++) t[i] = a[i];
        var b = new int[] { 1, 0, -1, 0 };
        var imax = n - 3;
        var s = a[0];
        var p = 0;
        for (int i = 0; i < imax; i++)
        {
            for (int j = 1; j < 4; j++)
                t[j - 1] = t[j] - b[j] * s;
            if (4 + p < n) t[3] = a[4 + p];
            s = t[0];
            p++;
        }
        if (t[0] == 0)
        {
            if (t[1] == 0) Console.WriteLine("0\n{0}", t[2]);
            else Console.WriteLine("1\n{0} {1}", t[2], t[1]);
        }
        else Console.WriteLine("2\n{0} {1} {2}", t[2], t[1], t[0]);
    }
}