let readString() = stdin.ReadLine()
let readStringArray() = stdin.ReadLine().Split(' ');
let readInt() = readString() |> int
let readIntArray() = readStringArray() |> Array.map(fun x -> int x)
let char2String(value) = List.ofSeq value |> List.toArray |> System.String

let list = [for i in [1..5] -> readInt()] 
let k = readInt()

if (list.[list.Length - 1] - list.[0]) <= k then "Yay!" else ":("
|> printfn "%s"