require 'to_words'

# find all the nine-digit numbers made up of only zeros and eights
possibilities = [0, 8]
8.times do
  new_possibilities = []
  possibilities.each do |possibility|
    new_possibilities << possibility * 10
    new_possibilities << possibility * 10 + 8
  end
  possibilities += new_possibilities
end

# add a five to all of them
possibilities.collect! {|p| p * 10 + 5}

winner = possibilities.inject('zzz') do |earliest, current|
  word = current.to_words
  raise "Unexpected number: #{current}" if word.eql? '?'
  word < earliest ? word : earliest
end
puts winner