#include <bits/stdc++.h>
using namespace std;
using ll=long long;
int main() {
	int n;
	cin >> n;
	vector<ll> a(n + 1);
	vector<ll> b(n + 1);
	for (int i = 1;i <= n;i++) {
		cin >> a[i];
	}
	for (int i = 1;i <= n;i++) {
		cin >> b[i];
	}
    long double left = 0, right = n;
    for (int i = 1; i <= n; i++) {
        right = max(right, (long double)a[i] / b[i]);
    }
    auto check = [&](long double x) {
        vector<long double> s(n + 1);
        vector<long double> preMin(n + 1);
        vector<long double> sufMax(n + 1);
        long double c = 1e100L;
        for (int i = 1;i <= n;i++) {
            s[i] = s[i - 1] + a[i] - x * b[i];
        }
        for (int i = 0; i < n;i++) {
            c = min(c, s[i]);
            preMin[i + 1] = c;
        }
        c = -1e100L;
        for (int i = n;i >= 1;i--) {
            c = max(c, s[i]);
            sufMax[i] = c;
        }
        for (int i = 1;i <= n;i++) {
            if (sufMax[i] <= preMin[i]) {
                return true;
            }
        }
        return false;
    };
    while (right - left > 0.000001) {
        long double mid = (left + right) / 2;
        if (check(mid)) right = mid;
        else left = mid;
    }
    cout << fixed << setprecision(7) << left << endl;
}