open System
open System.Collections.Generic

[<AutoOpen>]
module Cin =
    let read f = stdin.ReadLine() |> f
    let reada f = stdin.ReadLine().Split() |> Array.map f
    let readChars() = read string |> Seq.toArray
    let readInts() = readChars() |> Array.map (fun x -> Convert.ToInt32(x.ToString()))

[<AutoOpen>]
module Cout =
    let writer = new IO.StreamWriter(new IO.BufferedStream(Console.OpenStandardOutput()))
    let print (s: string) = writer.Write s
    let println (s: string) = writer.WriteLine s
    let inline puts (s: ^a) = string s |> println

let main() =
    let xs = readInts() |> Array.sortDescending
    let ng = xs |> Array.forall (fun x -> x = xs.[0])
    if ng then
        printfn "-1"
        exit 0

    let ys = xs |> Array.skipWhile (fun x -> x = xs.[0])
    let head = xs |> Array.takeWhile (fun x -> x = xs.[0])
    let same = ys |> Array.forall (fun y -> y = ys.[0])

    let ys =
        if same then
            let t = head.[0]
            head.[0] <- ys.[0]
            ys.[0] <- t
            Array.append head ys
        else
            let yh = ys |> Array.takeWhile (fun y -> y = ys.[0])
            let yt = ys |> Array.skipWhile (fun y -> y = ys.[0])
            let t = yh.[0]
            yh.[0] <- yt.[0]
            yt.[0] <- t
            Array.concat [| head; yh; yt |]

    if ys.[0] = 0 then puts -1 else String.Join("", ys) |> puts
    ()

main()
writer.Close()