import copy,heapq
N = int(raw_input())
_A = zip(map(int,raw_input().split()),[0]*N)
B = map(int,raw_input().split())

ans = 1500
for sp in xrange(N):
    A = copy.deepcopy(_A)
    heapq.heapify(A)
    for i in xrange(sp, N+sp):
        i %= N
        a = list(heapq.heappop(A))
        a[0] += B[i]/2
        a[1] += 1
        heapq.heappush(A,tuple(a))
    ans = min(ans, max(heapq.heappop(A)[1] for i in xrange(N)))
print ans