import Control.Applicative
import Data.List
import Data.Function
import qualified Data.IntMap as IM

slide n bs = drop n $ take (n+length bs) $ cycle bs

solve :: IM.IntMap Int -> [Int] -> Int
solve as bs = minimum $ [iter as $ (slide i bs)|i<-[0..length bs]] where
  iter a [] = snd $ maximumBy (compare `on` snd) $ IM.assocs a
  iter a (d:ds) = iter a' ds where
    Just ((n,c),b') = IM.minViewWithKey $ a
    a' = IM.insert (n+(d`div`2)) (c+1) b'

main = do
  _ <- getLine
  as <- fmap (read :: String -> Int) . words <$> getLine
  bs <- fmap (read :: String -> Int) . words <$> getLine
  print $ solve (IM.fromList $ zip as [0,0..]) bs