using System;
using System.Linq;
using System.Collections.Generic;

public class Program
{
    public void Proc() {
        Reader.IsDebug = false;
        long ans = GetAns(long.Parse(Reader.ReadLine()));
        Console.WriteLine(ans);
    }

    private Dictionary<long, long> dic = new Dictionary<long, long>();
    

    private long GetAns(long num) {
        if(dic.ContainsKey(num)) {
            return dic[num];
        }

        long ans = 0;

        string numstr = num.ToString();
        if(numstr.Length < 3) {
            return 0;
        }

        for(int i=0; i<numstr.Length - 2; i++) {
            if(numstr[i] == '0') {
                continue;
            }
            char[] numList = numstr.Skip(i+1).Where(a=>numstr.Skip(i+1).Count(b=>b==a)>1 && a != numstr[i]).ToArray();
            numList.ToList().ForEach(a=>{
                long newNum = long.Parse(numstr[i].ToString() + a + a);
                List<char> tmp = numstr.ToList();
                
                tmp.RemoveAt(numstr.IndexOf(a, i));
                tmp.RemoveAt(numstr.IndexOf(a, i));
                tmp.RemoveAt(i);
                long ret = 0;
                if(tmp.Count > 0) {
                    ret = this.GetAns(long.Parse(string.Join(string.Empty, tmp)));
                }
                ans = Math.Max(ans, ret + newNum);                
            });
        }
        dic[num] = ans;
        return ans;
    }

    public class Reader {
        public static bool IsDebug = true;
        private static System.IO.StringReader SReader;
        private static string InitText = @"


2718281828



";
        public static string ReadLine() {
            if(IsDebug) {
                if(SReader == null) {
                    SReader = new System.IO.StringReader(InitText.Trim());
                }
                return SReader.ReadLine();
            } else {
                return Console.ReadLine();
            }
        }
    }
    public static void Main(string[] args)
    {
        Program prg = new Program();
        prg.Proc();
    }
}