package main

import (
	"fmt"
	"sort"
)

func main() {
	var x string
	fmt.Scan(&x)
	m := make(map[int]int, 0)
	for i := 0; i < len(x); i++ {
		m[int(x[i]-'0')]++
	}
	ks := make([]int, 0)
	for k := range m {
		ks = append(ks, k)
	}
	sort.Sort(sort.Reverse(sort.IntSlice(ks)))
	maxs := ""
	for i := range ks {
		for j := 0; j < m[ks[i]]; j++ {
			maxs += string('0' + byte(ks[i]))
		}
	}
	ans := -1
	for i := len(maxs) - 1; i-1 >= 0; i-- {
		if maxs[i-1] != maxs[i] {
			s := maxs[0:i-1] + string(maxs[i]) + string(maxs[i-1])
			if i+1 < len(maxs) {
				s += string(maxs[i+1:])
			}
			if s[0] == '0' {
				break
			} else {
				fmt.Println(s)
				return
			}
		}
	}
	fmt.Println(ans)
}