using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{   

    public static void Main()

    {

            List<int> numbers = new List<int>() { 211, 2, 80, 81, 809 };

            Dictionary<string, string> numDic = new Dictionary<string, string>();

            string resStr = string.Empty;

            int countMaxDig = numbers.Max().ToString().Length;

            string tempNum = string.Empty;

​

            foreach (var num in numbers)

            {

                for (int i = (countMaxDig - num.ToString().Length); i > 0; i--)

                {

                    tempNum += num.ToString()[0];

                }

                numDic.Add(num.ToString(), num.ToString() + tempNum);

            }

​

            numDic = numDic.OrderByDescending(pair => pair.Value).ToDictionary(pair => pair.Key, pair => pair.Value);

            var keysList = numDic.Keys.ToList();

​

            foreach (var key in keysList)

            {

                resStr += key;

            }

​

            Console.WriteLine(resStr);

    }

}