module Main where

import Control.Monad (replicateM, replicateM_)
import Data.List (sort, transpose)

solve :: (Ord a) => [[a]] -> Bool
solve grid = all (\xs -> xs == sort xs) $ transpose $ map sort grid

main :: IO ()
main = do
    cases <- readLn :: IO Int
    replicateM_
        cases
        ( do
            n <- readLn :: IO Int
            grid <- replicateM n getLine
            putStrLn $ if solve grid then "YES" else "NO"
        )