import Control.Monad
import Data.List (sort)

main :: IO ()
main = do
  [h, w] <- f
  replicateM h f >>= solve w
  where
    f = map read <$> words <$> getLine

solve :: Int -> [[Int]] -> IO ()
solve w ass = f as
  where
    as = sort $ concat ass
    f xs = do
      case xs of
        [] -> return ()
        _ -> do
          putStrLn $ unwords $ map show $ take w xs
          f (drop w xs)