[<AutoOpen>]
module Program

open System

let read f = stdin.ReadLine() |> f
let reads f = stdin.ReadLine().Split() |> Array.map f

let rec f x = function
    | [] -> true
    | y :: ys -> if x = y then false else f y ys

[<EntryPoint>]
let main argv =
    let s = read string
    s.ToCharArray()
    |> List.ofArray
    |> fun (x :: xs) -> f x xs
    |> fun b -> if b then "Good" else "Bad"
    |> printfn "%s"
    0