require 'set'
_a = "aaeiuu".chars.permutation(6).to_a.uniq
_b = "bgmnr".chars.permutation(5).to_a.uniq
s = Set.new
_a.each do |a|
  _b.each do |b|
    s << ("" << a[0] << b[0] << a[1] << b[1] << a[2] << b[2] << a[3] << b[3] << a[4] << b[4] << a[5])
    s << ("" << b[0] << a[0] << a[1] << b[1] << a[2] << b[2] << a[3] << b[3] << a[4] << b[4] << a[5])
    s << ("" << b[0] << a[0] << b[1] << a[1] << a[2] << b[2] << a[3] << b[3] << a[4] << b[4] << a[5])
    s << ("" << b[0] << a[0] << b[1] << a[1] << b[2] << a[2] << a[3] << b[3] << a[4] << b[4] << a[5])
    s << ("" << b[0] << a[0] << b[1] << a[1] << b[2] << a[2] << b[3] << a[3] << a[4] << b[4] << a[5])
    s << ("" << b[0] << a[0] << b[1] << a[1] << b[2] << a[2] << b[3] << a[3] << b[4] << a[4] << a[5])
  end
end
gets.to_i.times do
  s.delete gets.chomp
end
if s.empty?
  puts :NO
else
  puts s.first
end