antennas = []
5.times do
  antennas << gets.to_i
end
max = gets.to_i
c = 0
for i in 0..4
  for j in 1..3
    c += 1 if antennas[j] - antennas[i] > max
  end
end
if c > 0
  puts ":("
else
  puts "Yay!"
end