import Control.Monad
import Control.Applicative
import Data.List


main :: IO()
main = do
  list <- replicateM 5 readLn :: IO [Int]
  k <- readLn :: IO Int
  let list' = loop list
  let ans = if all (<=k) list'
              then "Yay!"
              else ":("
  putStrLn ans


loop :: [Int] -> [Int]
loop [x] = []
loop (x:xs) = [ d | y <- xs, let d = y - x] ++ loop xs
