import Control.Arrow
import Control.Monad
import Data.List
import qualified Data.ByteString.Char8 as B

main :: IO ()
main = readLine >>= main'
    where
        main' [n, m] = readContents n >>= print . solve n

solve :: Int -> [[Int]] -> Int 
solve n = length . filter (== n) . map length . group . sort . concatMap tail

readLine :: IO [Int]
readLine = unfoldr (\s -> second (maybe B.empty snd . B.uncons) <$> B.readInt s) <$> B.getLine

readContents :: Int -> IO [[Int]]
readContents = flip replicateM readLine

