let five_antennas a b c d e k = if e - a > k then ":(" else "yay!"

let a = read_int()
let b = read_int()
let c = read_int()
let d = read_int()
let e = read_int()
let k = read_int()

let () = Printf.printf "%s\n" (five_antennas a b c d e k)