a = []
 5.times do |i|
   a[i] = gets.to_i
end

k = gets.to_i

check = true

for i in 0..3
  for j in (i + 1)..4

    if k < (a[i] - a[j]).abs then
      check = false
    end

  end
end

if check then
  puts "Yay!"
else
  puts ":("
end