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

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define vin(vec, n) rep (i, n) cin >> vec[i];
using ll = long long;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using vc = vector<char>;
using vvc = vector<vector<char>>;
using pii = pair<int, int>;
const ll MOD = 998244353, MOD2 = 1000000007;
/************************************************************************************/

int main() {
  int N; cin >> N;
  vi A(N), B(N); vin(A, N); vin(B, N);
  double ok = 0.0, ng = 1000000001.0;
  while (abs(ok-ng) > 1e-7) {
    double x = (ok+ng)/2.0;

    vector<double> L(N), R(N);
    L[0] = 0.0;
    for (int i = 0; i < N-1; ++i)
      L[i+1] = max(0.0, L[i]+(A[i]-x*B[i]));
    R[N-1] = 0.0;
    for (int i = N-2; 0 <= i; --i)
      R[i] = max(0.0, R[i+1]+(A[i+1]-x*B[i+1]));

    bool flag = true;
    for (int k = 0; k < N; ++k) {
      if (L[k]+R[k]+A[k]-x*B[k] < 0) {
        flag = false; break;
      }
    }
    if (flag) ok = x;
    else ng = x;
  }
  cout << fixed << setprecision(10) << ok << '\n';
}