namespace AtCoder;

#nullable enable

using System.Numerics;

static class Extensions
{
    public static T[] Repeat<T>(this int time, Func<T> F) => Enumerable.Range(0, time).Select(_ => F()).ToArray();
}

class AtCoder
{
    object? Solve()
    {
        var n = Int();
        var m = Int();
        var b = new List<int>();
        var o = new HashSet<int>();
        var q = new PriorityQueue<(int, int), (int, int)>();
        var max = int.MaxValue;
        var c = new HashSet<int>();
        Int();
        for (var i = 1; i < n; i++)
        {
            var a = Int();
            q.Enqueue((a, 0), (a, 0));
        }
        while (q.Count > 0)
        {
            var (v, k) = q.Dequeue();
            if (k == 0)
            {
                o.Add(v);
                if (c.Contains(v)) continue;
                b.Add(v);
                c.Add(v);
                var v2 = v * 2;
                if (v2 > m) continue;
                c.Add(v2);
                q.Enqueue((v2, v), (v2, v));
            }
            else
            {
                if (!o.Contains(v)) return -1;
                var v2 = v + k;
                if (v2 > m) continue;
                c.Add(v2);
                q.Enqueue((v2, k), (v2, k));
            }
        }
        Out(b.Count);
        Out(b, " ");
        return null;
    }

    public static void Main() => new AtCoder().Run();
    public void Run()
    {
        var res = Solve();
        if (res != null)
        {
            if (res is bool yes) res = yes ? "Yes" : "No";
            sw.WriteLine(res);
        }
        sw.Flush();
    }

    string[] input = Array.Empty<string>();
    int iter = 0;
    readonly StreamWriter sw = new(Console.OpenStandardOutput()) { AutoFlush = false };

    string String()
    {
        while (iter >= input.Length) (input, iter) = (Console.ReadLine()!.Split(' '), 0);
        return input[iter++];
    }
    T Input<T>() where T : IParsable<T> => T.Parse(String(), null);
    int Int() => Input<int>();
    void Out(object? x, string? separator = null)
    {
        separator ??= Environment.NewLine;
        if (x is System.Collections.IEnumerable obj and not string)
        {
            var firstLine = true;
            foreach (var item in obj)
            {
                if (!firstLine) sw.Write(separator);
                firstLine = false;
                sw.Write(item);
            }
        }
        else sw.Write(x);
        sw.WriteLine();
    }
}