package main

import . "fmt"
import . "slices"

func main() {
	var s string
	Scan(&s)
	b := []byte(s)
	Sort(b)
	for i := range b[1:] {
		if b[i] != b[i+1] {
			b[i],b[i+1]=b[i+1],b[i]
			break
		}
	}
	Reverse(b)
	if b[0]==b[len(b)-1] || b[0]=='0' {
		Println(-1)
	} else {
		Println(string(b))
	}
}