a,b,c,d,e,k = gets.chomp.to_i,gets.chomp.to_i,gets.chomp.to_i,gets.chomp.to_i,gets.chomp.to_i,gets.chomp.to_i
result = []
result << (a-b).abs
result << (a-c).abs
result << (a-d).abs
result << (a-e).abs
result << (b-c).abs
result << (b-d).abs
result << (b-e).abs
result << (c-d).abs
result << (c-e).abs
result << (d-e).abs
i = 0
while result.size != i
  if result[i] <= k
  else
    puts ":("
    exit
  end
  i+=1
end
puts "Yay!"
exit
