def dist(a, b)
  (a - b).abs
end

dists = []

dists << STDIN.gets.to_i
dists << STDIN.gets.to_i
dists << STDIN.gets.to_i
dists << STDIN.gets.to_i
dists << STDIN.gets.to_i

threshold = STDIN.gets.to_i

if dists.combination(2).any? {|a, b| dist(a, b) > threshold}
  STDOUT.puts ':('
else
  STDOUT.puts 'Yay!'
end