module Main where

import qualified Data.Map  as M
import qualified Data.Set  as S

dist :: [Int] -> M.Map Int Int
dist xs = M.fromListWith (+) [(x, 1) | x <- xs]

solve :: [Int] -> [Int] -> Int
solve as bs = do
    let sab = S.fromList $ as ++ bs
    let mbase = M.fromList [(x, 0) | x <- S.elems sab]
    let ma = M.unionWith (+) mbase $ dist as
    let mb = M.unionWith (+) mbase $ dist bs
    let naturals = sum $ M.unionWith min ma mb
    let deltas = M.unionWith (-) mb ma
    let nonzeros = M.filter (/= 0) deltas
    let (poss, negs) = M.partition (> 0) nonzeros
    let correction = if null poss || null negs then -1 else 1
    naturals + correction

main :: IO ()
main = do
    _ <- getLine
    as <- map read . words <$> getLine :: IO [Int]
    bs <- map read . words <$> getLine :: IO [Int]
    print $ solve as bs