SequenceNM

using System;
using System.Collections.Generic;

namespace SequenceNM
{
    class Program
    {
        static void Main()
        {
            string[] input = Console.ReadLine().Split(' ');
            int n = int.Parse(input[0]);
            int m = int.Parse(input[1]);
            if (n == m)
            {
                Console.WriteLine(n);
                return;
            }
            else if (n >= m)
            {
                Console.WriteLine("");
                return;
            }
            else
            {
                int outNumber = int.MinValue;
                Queue<int> queueNumbers = new Queue<int>();
                List<int> list = new List<int>();
                List<int> outSequence = new List<int>();
                Queue<List<int>> queueSequences = new Queue<List<int>>();
                queueNumbers.Enqueue(n);
                list.Add(n);
                queueSequences.Enqueue(list);
                while (true)
                {
                    int currentCount = queueNumbers.Count;
                    for (int i = 0; i < currentCount; i++)
                    {
                        outNumber = queueNumbers.Dequeue();
                        if (outNumber == m)
                        {
                            list = queueSequences.Dequeue();
                            Console.WriteLine(string.Join(" -> ", list.ToArray()));
                            return;
                        }
                        outSequence = queueSequences.Dequeue();

                        queueNumbers.Enqueue(outNumber + 1);
                        outSequence.Add(outNumber + 1);
                        queueSequences.Enqueue(outSequence);
                        outSequence.RemoveAt(outSequence.Count - 1);

                        queueNumbers.Enqueue(outNumber + 2);
                        outSequence.Add(outNumber + 2);
                        queueSequences.Enqueue(outSequence);
                        outSequence.RemoveAt(outSequence.Count - 1);

                        queueNumbers.Enqueue(2 * outNumber);
                        outSequence.Add(2 * outNumber);
                        queueSequences.Enqueue(outSequence);
                        outSequence.RemoveAt(outSequence.Count - 1);
                    }
                }
            }
        }
    }
}