#include <bits/stdc++.h>
#define fi first
#define se second
#define rep(i,s,n) for (int i = (s); i < (n); ++i)
#define rrep(i,g,n) for (int i = (n)-1; i >= (g); --i)
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define len(x) (int)(x).size()
#define dup(x,y) (((x)+(y)-1)/(y))
#define pb push_back
#define eb emplace_back
#define Field(T) vector<vector<T>>
using namespace std;
using ll = long long;
using ull = unsigned long long;
template<typename T> using pq = priority_queue<T,vector<T>,greater<T>>;
using P = pair<int,int>;
template<class T>bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T>bool chmin(T&a,T b){if(b<a){a=b;return 1;}return 0;}

int main() {
  int n;
  cin >> n;
  vector<int> a(n), b(n);
  rep(i,0,n) cin >> a[i];
  rep(i,0,n) cin >> b[i];
  function<bool(double)> f = [&](double c) {
    vector<double> s(n+1);
    rep(i,0,n) s[i+1] = s[i]-c*b[i]+a[i];
    vector<double> x(n+1), y(n+1);
    x[0] = s[0], y[n] = s[n];
    rep(i,1,n+1) x[i] = min(x[i-1], s[i]);
    rrep(i,0,n) y[i] = max(y[i+1], s[i]);
    rep(i,0,n) {
      if (x[i] > y[i+1]) return false;
    }
    return true;
  };
  double ok = 0.0, ng = 1e15;
  int step = 100;
  while(step--) {
    double mid = (ok+ng)/2.0;
    if (f(mid)) ok = mid;
    else ng = mid;
  }
  printf("%.10lf\n", ok);
  return 0;
}