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

def f(P):
    d = [0] + [A[i] - P*B[i] for i in range(N)]
    for i in range(1,N+1):
        d[i] += d[i-1]
    d_min = d[::]
    for i in range(1,N+1):
        d_min[i] = min(d_min[i], d_min[i-1])
    d_max = d[::]
    for i in range(N-1,-1,-1):
        d_max[i] = max(d_max[i], d_max[i+1])
    for i in range(N):
        if d[i] + d_max[i+1] - d_min[i] < 0:
            return False
    return True


left,right=1,10**9+1
while right - left > 10**(-7):
    mid = (left + right)/2
    if f(mid):
        left = mid
    else:
        right = mid
print(left)