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

class Iroha
{
    public Iroha() { }
    public static int Main()
    {
        new Iroha().calc();
        return 0;
    }

    Scanner cin;

    void calc()
    {
        cin = new Scanner();
        string S = cin.next();
        int[] dp = new int[1 << S.Length];

        int ans = 0;
        for (int t = 0; t < (1 << S.Length); t++)
        {
            ans = Math.Max(dp[t], ans);
            if (t != 0 && dp[t] == 0) continue;
            for (int j = 1; j < S.Length; j++)
            {
                if ((t >> j) % 2 == 1) continue;
                for (int k = j + 1; k < S.Length; k++)
                {
                    if (S[j] != S[k]) continue;
                    if ((t >> k) % 2 == 1) continue;
                    for (int i = 0; i < j; i++)
                    {
                        if ((t >> i) % 2 == 1) continue;
                        if (S[i] == '0') continue;
                        if (S[i] == S[j]) continue;
                        int next = t + (1 << i) + (1 << j) + (1 << k);
                        dp[next] = Math.Max(dp[next], dp[t] + (S[i] - '0') * 100 + (S[j] - '0') * 10 + (S[k] - '0'));
                    }
                }
            }
        }
        Console.WriteLine(ans);
    }
}


class Scanner
{
    string[] s;
    int i;

    char[] cs = new char[] { ' ' };

    public Scanner()
    {
        s = new string[0];
        i = 0;
    }

    public string next()
    {
        if (i < s.Length) return s[i++];
        string st = Console.ReadLine();
        while (st == "") st = Console.ReadLine();
        s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
        i = 0;
        return next();
    }

    public int nextInt()
    {
        return int.Parse(next());
    }

    public long nextLong()
    {
        return long.Parse(next());
    }

    public double nextDouble()
    {
        return double.Parse(next());
    }

}