antinas = 5.times.map{gets.to_i}
k=gets.to_i
nonSendflag = false
(0..3).each do |index|
  p = antinas[index]
  antinas[(index+1)..4].each do |q|
    if k < q-p
      nonSendflag = true
      break
    end
  end
  break if nonSendflag
end
puts nonSendflag ? ":(" : "Yay!" 