#!/usr/bin/env python3

k = int(input())
ts = map(int, input().split())
ss = map(int, input().split())

d = sorted(zip(ts, ss), key=lambda x: x[1])
T = 0
ans = 0
for t, s in d:
    if s == -1:
        continue
    T += t
    ans = max(ans, (T + s - 1) // s)
print(ans)