# encoding: utf-8
anten = []
5.times do
  x = gets.chomp.to_i
  anten << x
end
K = gets.chomp.to_i
# p anten
# p K
f = true
for i in 0..3 do
  for j in (i+1)..4 do
    if (anten[j] - anten[i]) > K then
      f = false
      break;
    end
  end
end
if f then
  puts 'Yay!'
else
  puts ':('
end