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

using namespace std;

int main() {
    int n;
    cin >> n;
    
    vector<double> a(n), b(n);
    rep(i, n) cin >> a[i];
    rep(i, n) cin >> b[i];
    
    double ac = 1e14, wa = 0;
    rep(ti, 100) {
        double wj = (ac+wa)/2;
        
        auto ok = [&]{
            vector<double> p(n+1);
            rep(i, n) p[i+1] = p[i] + (a[i]-wj*b[i]);
            
            vector<double> lmn(n+1);
            double now = p[0];
            for (int i = 1; i <= n; ++i) {
                lmn[i] = now;
                now = min(now, p[i]);
            }
            
            vector<double> rmx(n+1);
            rmx[n] = p[n];
            for (int i = n-1; i >= 1; --i) {
                rmx[i] = max(rmx[i+1], p[i]);
            }
            
            for (int i = 1; i <= n; ++i) {
                if (rmx[i] <= lmn[i]+1e-11) {
                    return true;
                }
            }
            
            return false;
        }();
        
        (ok ? ac : wa) = wj;
    }
    
    printf("%.10f\n", ac);
    
    return 0;
}