import heapq

n = int(input())
a_ls = [int(a) for a in input().split()]
b_ls = [int(b) for b in input().split()]

hq_o = [(a, 0) for a in a_ls]
heapq.heapify(hq_o)

hb_ls = [b // 2 for b in b_ls]
hdb_ls = hb_ls + hb_ls

ans = n
for i in range(n):
    hq = hq_o[:]
    
    for hb in hdb_ls[i:i + n]:
        lv, ct = hq[0]
        heapq.heapreplace(hq, (lv + hb, ct + 1))
    
    ans = min(ans, max([ct for lv, ct in hq]))

print(ans)