a = gets.to_i
b = gets.to_i
c = gets.to_i
d = gets.to_i
e = gets.to_i
k = gets.to_i
arr = [a,b,c,d,e]

def five_antennas(arr, k)
  for i in 1..4 do
    if (arr[i] - arr[i+1]) < k
      return "Yay!"
    end
    ":("
  end
end

puts five_antennas(arr, k)
