import Data.List
import Control.Applicative
import Control.Monad

main = do
  n <- readLn
  names <- replicateM n getLine
  let perm1 = permutations "iaaeuu"
      perm2 =  permutations "nbgmr*"
      newNames = map (delete '*') [ins c v | v <- perm1, c <- perm2] \\ names
  case newNames of
      [] -> putStrLn "NO"
      _ -> putStrLn $ head newNames

legal [] = True
legal [charo] = charo `elem` "iaeu" 
legal (charo1 : charo2 : str) = if charo1 `elem` "iaeu"
                                    then legal (charo2 : str)
                                    else charo2 `elem` "iaeu" && legal str

ins [c1, c2, c3, c4, c5, c6] [v1, v2, v3, v4, v5, v6] = [c1, v1, c2, v2, c3, v3, c4, v4, c5, v5, c6, v6]