from collections import deque, defaultdict, Counter
from bisect import bisect_left, bisect_right, insort
from itertools import permutations, combinations, groupby
from heapq import heappop, heappush
import math, sys
input = lambda: sys.stdin.readline().rstrip("\r\n")
def printl(li, sep=" "): print(sep.join(map(str, li)))
def yn(flag): print(Yes if flag else No)
_int = lambda x: int(x)-1
MOD = 998244353 #10**9+7
INF = 1<<60
Yes, No = "Yes", "No"

N = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))

def check(m):
    C = [A[i]-B[i]*m for i in range(N)]
    cum = [0]
    for c in C: cum.append(cum[-1]+c)
    res = [0]*N
    mn = 0
    for i in range(N):
        res[i] += cum[i]-mn + C[i]
        mn = min(mn, cum[i+1])
    mx = cum[N]
    r = True
    for i in reversed(range(N)):
        res[i] += mx-cum[i+1]
        mx = max(mx, cum[i])
        if res[i] < 0: r = False
    return r

l, r = 0, 10**10
for _ in range(100):
    m = (l+r)/2
    if check(m): l = m
    else: r = m
print(l)