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

#define EPS (1e-12L)
using ld = long double;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int n; cin >> n;
    vector<ld> a(n), b(n);
    for (auto& i : a) cin >> i;
    for (auto& i : b) cin >> i;
    
    ld m = 0, M = 0;
    
    for (int i=0; i<n; i++) M = max(M, a[i]/b[i]);
    
    auto f = [&](ld x) -> bool {
    	vector<ld> c(n), d(n);
    	for (int i=0; i<n; i++) c[i] = a[i] - b[i] * x;
    	d.back() = c.back();
    	for (int i=n-2; 0<=i; i--) d[i] = c[i] + max(0.0L, d[i+1]);
    	ld l = 0;
    	for (int i=0; i<n; i++) {
    		l = c[i] + max(0.0L, l);
    		if (l+d[i]-c[i] <= 0) return true;;
    	}
    	return false;
    };;
    int x = 100;
    while (x--) {
    	ld mid = (m + M) / 2;
    	if (f(mid)) {
    		M = mid;
    	} else {
    		m = mid;
    	}
    }
    
    cout << fixed << setprecision(15) << M << '\n';
}