using System;
using System.Linq;

namespace y
{
    class Program
    {
        static void Main(string[] args)
        {
            string n = Console.ReadLine();
            string a = "";
            int cnt = n.Count(x => x == '9');
            for (int i = 0; i < cnt; i++)
            {
                a += "9";
            }

            cnt = n.Count(x => x == '8');
            for (int i = 0; i < cnt; i++)
            {
                a += "8";
            }

            cnt = n.Count(x => x == '7');
            for (int i = 0; i < cnt; i++)
            {
                a += "7";
            }

            cnt = n.Count(x => x == '6');
            for (int i = 0; i < cnt; i++)
            {
                a += "6";
            }

            cnt = n.Count(x => x == '5');
            for (int i = 0; i < cnt; i++)
            {
                a += "5";
            }

            cnt = n.Count(x => x == '4');
            for (int i = 0; i < cnt; i++)
            {
                a += "4";
            }

            cnt = n.Count(x => x == '3');
            for (int i = 0; i < cnt; i++)
            {
                a += "3";
            }

            cnt = n.Count(x => x == '2');
            for (int i = 0; i < cnt; i++)
            {
                a += "2";
            }

            cnt = n.Count(x => x == '1');
            for (int i = 0; i < cnt; i++)
            {
                a += "1";
            }

            cnt = n.Count(x => x == '0');
            for (int i = 0; i < cnt; i++)
            {
                a += "0";
            }

            Console.WriteLine(a);
        }
    }
}