main = do
    a <- readLn :: IO Integer
    b <- readLn :: IO Integer
    c <- readLn :: IO Integer
    d <- readLn :: IO Integer
    e <- readLn :: IO Integer
    k <- readLn :: IO Integer
    let ls = [ b - a
               , c - a
               , d - a
               , e - a
               , c - b
               , d - b
               , e - b
               , d - c
               , e - c
               , e - d
               ]
    if all (distance k) ls
    then print "Yay!"
    else print ":("
    
distance k d =
    if abs d <= k
    then True
    else False
