#nullable enable

​

using System;

using System.Collections.Generic;

using System.Linq;

​

class Bag

{

    public Int32 Value { get; set; }

​

    public Bag? Next { get; set; }

​

    public IEnumerable<Int32> Traverse()

    {

        yield return this.Value;

        if (this.Next == null) yield break;

        foreach (var value in this.Next.Traverse()) yield return value;

    }

​

    public IEnumerable<Int32> TraverseReverese()

    {

        return this.Traverse().Reverse();

    }

}

​

public class Program

{

    public static void Main()

    {

        var bag = new Bag { Value = 1, Next = new Bag { Value = 2, Next = new Bag { Value = 3 } } };

        foreach (var value in bag.TraverseReverese()) Console.WriteLine(value);

    }

}