arr = []
5.times do |i|
    a = gets.chomp.to_i
    arr << a
end
k = gets.chomp.to_i
kkk = []
arr.each do |f|
    arr.each do |k|
       kkk << (f - k).abs 
    end
end

until kkk == []
    aaa = kkk.pop
    if aaa >= k
        puts ":("
        exit
    end
end
puts "Yay!"