allowed_chars = 'AS49BWXCcahpnz07'.chars

regex = File.read('regex.txt')
patterns = regex.split('|')[3..-1]

unallowed_chars = Hash.new([])
patterns.each do |pattern|
  position = pattern.match(/\{(\d*)\}/)[1].to_i # get digits inside {}
  chars = pattern.match(/\[(.*)\]/)[1].chars    # get characters inside []
  unallowed_chars[position] += chars
end

str = 196.times.map { |i| (allowed_chars - unallowed_chars[i])[0] }.join
puts str