package main

import (
        "bufio"
        "fmt"
        _ "math"
        _ "math/big"
        "os"
        _ "reflect"
        _ "regexp"
        "strconv"
        _ "strings"
)

func callable(ns []string, bs []bool) int64 {
        res := int64(0)
        for i := 0; i < len(ns); i++ {
                if bs[i] == true {
                        continue
                }
                for j := i + 1; j < len(ns); j++ {
                        if bs[j] == true {
                                continue
                        }
                        for k := j + 1; k < len(ns); k++ {
                                if bs[k] == true {
                                        continue
                                }
                                if ns[i] != "0" && ns[i] != ns[j] && ns[j] == ns[k] {
                                        x, _ := strconv.ParseInt(ns[i]+ns[j]+ns[k], 10, 64)
                                        bs[i], bs[j], bs[k] = true, true, true
                                        comp := x + callable(ns, bs)
                                        if res < comp {
                                                res = comp
                                        }
                                        bs[i], bs[j], bs[k] = false, false, false
                                }
                        }
                }
        }
        return res
}

func main() {
        scanner := bufio.NewScanner(os.Stdin)
        th := 0
        lines := []string{}
        for scanner.Scan() {
                th += 1
                text := scanner.Text()
                lines = append(lines, text)
                if th == 1 {
                        break
                }
        }
        bs := []bool{}
        tn := lines[0]
        ns := []string{}
        for _, x := range []rune(tn) {
                ns = append(ns, string(x))
                bs = append(bs, false)
        }
        fmt.Println(callable(ns, bs))
}