import Control.Applicative
import Control.Monad
import Data.Array
import Data.Maybe
import qualified Data.Set as S
import Debug.Trace

rotates s = f s $ reverse s
  where
    n = length s
    f xs []     = [xs]
    f xs (y:ys) = xs:f (take n (y:xs)) ys

main = do
  _ <- getLine
  a <- map read . words <$> getLine
  b <- map ((`div`2).read) . words <$> getLine
  let
    pq = foldl (flip S.insert) S.empty $ map (\i->(i,0)) a
    check m elevels =min m $ last . fst $ break (>m) $ map fst $ scanl f (0,pq) $ elevels
    f (mn,tpq) elevel = (max mn (cnt+1),S.insert (level+elevel,cnt+1) gotpq)
      where
        ((level,cnt),gotpq) = S.deleteFindMin tpq
  print $ foldl check (10^4) $ rotates b