{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE BinaryLiterals #-}
{-# LANGUAGE MultiWayIf #-}
{-# LANGUAGE NumDecimals #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TupleSections #-}

import Control.Applicative
import Control.Arrow
import Control.Monad
import Control.Monad.ST

import Data.Char
import Data.List
import Data.Maybe

import qualified Data.ByteString.Char8 as B

import Data.Array.ST.Safe
import Data.STRef

import Debug.Trace
import Text.Printf

readInt = readLn :: IO Int
readInteger = readLn :: IO Integer
readInts = map ( fst . fromJust . B.readInt ) . B.words <$> B.getLine
readIntegers = map ( fst . fromJust . B.readInteger ) . B.words <$> B.getLine

which a b f = if f then a else b
mp [ a, b ] = ( a, b )

modifyArray a i f = writeArray a i =<< f <$> readArray a i

main = do
	[ _, k ] <- readIntegers
	as <- sort <$> readIntegers
	fs <- readIntegers
	print $ solve as fs k (-1) ( 10 ^ 18 :: Integer )

solve as fs k lb ub 
	| lb + 1 < ub = if possible as fs k mid
		then solve' lb mid
		else solve' mid ub
	| otherwise = ub
	where
		mid = ( lb + ub ) `div` 2
		solve' = solve as fs k

possible as fs k lim = cost <= k
	where
		bs = sort $ map ( lim `div` ) fs
		cost = sum $ map ( max 0 ) $ zipWith (-) as bs