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 az = n.Repeat(Int);
        var lz = new Dictionary<int, int>();
        var rz = new Dictionary<int, int>();
        for (var i = 0; i < n; i++)
        {
            var a = az[i];
            if (rz.ContainsKey(a))
            {
                Out(0);
                Out("");
                return null;
            }
            if (lz.ContainsKey(a)) rz[a] = i;
            else lz[a] = i;
        }
        foreach (var lv in lz.Keys) if (!rz.ContainsKey(lv)) lz.Remove(lv);
        var l = 0;
        if (lz.Count > 0) l = lz.Values.Max();
        var r = n - 1;
        if (rz.Count > 0) r = rz.Values.Min();
        var ans = new List<int>();
        for (var i = l; i < r; i++) ans.Add(i + 1);
        Out(ans.Count);
        Out(ans, " ");
        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();
    }
}