import Control.Applicative ((<$>))
import qualified Data.ByteString.Char8 as SC
import Data.List (sortBy)
import Data.Maybe (fromJust)

data Color = White | Black deriving (Enum, Show)
type Block = Int

unsafeReadInt :: SC.ByteString -> Int
unsafeReadInt = fst . fromJust . SC.readInt

maxHeight :: [Block] -> [Block] -> Int
maxHeight ws0 bs0 = max candw candb
    where
        ws1 = sortBy (flip compare) ws0
        bs1 = sortBy (flip compare) bs0
        candw = mh 0 maxBound White ws1 bs1
        candb = mh 0 maxBound Black ws1 bs1
        mh :: Int -> Int -> Color -> [Block] -> [Block] -> Int
        mh h _ White [] _ = h
        mh h _ Black _ [] = h
        mh h prev White (w : ws) bs
            | w < prev = mh (h + 1) w Black ws bs
            | otherwise = mh h prev White ws bs
        mh h prev Black ws (b : bs)
            | b < prev = mh (h + 1) b White ws bs
            | otherwise = mh h prev Black ws bs

main :: IO ()
main = do
    _ <- SC.getLine
    ws <- fmap unsafeReadInt . SC.words <$> SC.getLine
    _ <- SC.getLine
    bs <- fmap unsafeReadInt . SC.words <$> SC.getLine
    print $ maxHeight ws bs