import Data.List (permutations, elemIndex)
import Control.Applicative ((<$>))
import qualified Data.ByteString.Lazy.Char8 as B
import Data.Maybe (fromJust)

judge :: [Int] -> [Int] -> Int
judge is (i1 : i2 : s : _)
    | elemIndex i1 is < elemIndex i2 is = s
    | otherwise                         = 0

main :: IO ()
main = do
    [n, _] <- map read . words <$> getLine
    ts <- map (map (fst . fromJust . B.readInt)) . map B.words . B.lines <$> B.getContents
    print $ maximum $ map (\p -> sum $ map (judge p) ts) $ permutations [0 .. n - 1]