#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

int main() {
    cin.tie(nullptr);
    ios_base::sync_with_stdio(false);
    int n;
    cin >> n;
    vector<ll> a(n);
    vector<ll> b(n);
    rep(i, n) cin >> a[i];
    rep(i, n) cin >> b[i];
    double l = 0;
    ll sa = 0;
    ll sb = 0;
    rep(i, n) {
        sa += a[i];
        sb += b[i];
        l = max(l, double(sa) / sb);
    }
    double r = 0;
    reverse(a.begin(), a.end());
    reverse(b.begin(), b.end());
    sa = 0;
    sb = 0;
    rep(i, n) {
        sa += a[i];
        sb += b[i];
        r = max(r, double(sa) / sb);
    }
    cout << fixed << setprecision(12);
    cout << min(l, r) << endl;
    return 0;
}