# coding: utf-8
import heapq
N = int(raw_input())
A = map(int, raw_input().split())
B = [int(x)/2 for x in raw_input().split()]

A.sort()
Aheap = [(a, 0) for a in A]
B_ = list(B)
B.extend(B_)

ans = int(1e9+7)
for i in xrange(len(B_)):
	a = list(Aheap)
	for j in xrange(len(B_)):
		lv, c = a[0]
		#print str(lv) + ' ' + str(c)
		heapq.heapreplace(a, (lv+B[i+j], c+1))
		#print a
	ans=min(ans, max(c for lv, c in a))

print ans