def aa
	a = gets.chomp.to_i
	b = gets.chomp.to_i
	c = gets.chomp.to_i
	d = gets.chomp.to_i
	e = gets.chomp.to_i
	k = gets.chomp.to_i

    if
    (a-b).abs <= k and
    (a-c).abs <= k and
    (a-d).abs <= k and
    (a-e).abs <= k and
    (b-c).abs <= k and
    (b-d).abs <= k and
    (b-e).abs <= k and
    (c-d).abs <= k and
    (c-e).abs <= k and
    (d-e).abs <= k
        puts 'Yay!'
    else
        puts ':('
    end
end

aa
