list = []
count = 0
6.times do
  list << gets.chomp.to_i
end

for i in 0..4 do
  for j in (i + 1)..4 do
    if (list[j] - list[i]) > list[5]
      count += 1
    end
  end
end

if count != 0
  puts ":("
else
  puts "Yay!"
end
