#include <bits/stdc++.h>
using namespace std;

// k <= sum(a)/sum(b)
// k * sum(b) <= sum(a)
// k * sum(b) - sum(a) <= 0
int main() {
	int n; cin >> n;
	vector<double> a(n), b(n);
	for (int i = 0; i < n; ++i) cin >> a[i];
	for (int i = 0; i < n; ++i) cin >> b[i];
	double ok = 0, ng = *max_element(a.begin(), a.end());
	for (int _ = 0; _ < 100; _++) {
		double k = (ok + ng) / 2;
		vector<double> pmin(n + 1, 0), smin(n + 1, 0);
		double prefix = 0, suffix = 0;
		for (int i = 0; i < n; ++i) {
			prefix += a[i] - b[i] * k;
			suffix += a[n-i-1] - b[n-i-1] * k;
			pmin[i+1]   = min(pmin[i]  , prefix);
			smin[n-i-1] = min(smin[n-i], suffix);
		}
		double x = 1e18;
		for (int i = 0; i < n; ++i) {
			x = min(x, prefix - pmin[i] - smin[i+1]);
		}
		if (0 <= x) ok = k;
		else ng = k;
	}
	cout << fixed << setprecision(12);
	cout << ok << endl;
}