import Control.Applicative ((<$>))
import Control.Monad (replicateM)

import Data.ByteString.Char8 (ByteString)
import qualified Data.ByteString.Char8 as B

import Data.List

main :: IO ()
main = do
  n <- readLn
  solve n <$> replicateM n B.getLine >>= putStrLn

solve :: Int -> [ByteString] -> String
solve n ss = f 0 ls
  where
    ls = map length . group . sort $ ss
    f mx xs
      | null xs && mx == 0 = "YES"
      | null xs = "NO"
      | mx == 0 = f (m - 1) rs
      | otherwise = f (m - 1) (mx : rs)
      where
        m = maximum xs
        rs = delete m xs