[<AutoOpen>]
module Program

open System

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

[<EntryPoint>]
let main argv =
    let xs = List.map (fun _ -> read int) [1..5]
    let k = read int
    if List.last xs - List.head xs <= k
    then printfn "Yay!"
    else printfn ":("
    0