let x = stdin.ReadLine () |> Seq.sortDescending |> Seq.map string |> String.concat ""

let s = Set.ofSeq x
if x.Length = 1 || s.Count = 1 || (s.Count = 2 && s.Contains '0') then
    "-1"
else
    let mutable index = x.Length - 2
    while x.[index] = x.[index+1] do
        index <- index - 1
    (if index = 0 then "" else x.[..index-1]) + string x.[index+1] + string x.[index] + x.[index+2..]
|> printfn "%s"