import Control.Applicative ((<$>), (<*>))
import Data.List (sort)

main :: IO ()
main = solve <$> f <*> f >>= print
  where f = getLine >> map read <$> words <$> getLine
  

solve :: [Int] -> [Int] -> Int
solve ws bs = let ws' = sort ws
                  bs' = sort bs
              in max (f 0 0 ws' bs') (f 0 0 bs' ws')
  where f ht wt xs ys = let xs' = dropWhile (<= wt) xs
                        in case xs' of
                            (n:ns) -> f (ht+1) n ys ns
                            [] -> ht