a = gets.to_i
b = gets.to_i
c = gets.to_i
d = gets.to_i
e = gets.to_i
k = gets.to_i
arr = [a, b, c, d, e]
n = arr.count
res = 'Yay!'
n.times do |i|
  j = i + 1
  while j < n
    if k <= (arr[j] - arr[i])
      res = ':('
      break
    end
    j += 1
  end
  break if res === ':('
end
puts res