#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return true; } return false; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return true; } return false; }
#define vi vector<int>
#define vl vector<ll>
#define vii vector<pair<int,int>>
#define vll vector<pair<ll,ll>>
#define vvi vector<vector<int>>
#define vvl vector<vector<ll>>
#define vvii vector<vector<pair<int,int>>>
#define vvll vector<vector<pair<ll,ll>>>
#define vst vector<string>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define mkunique(x) sort(all(x));(x).erase(unique(all(x)),(x).end())
#define fi first
#define se second
#define mp make_pair
#define si(x) int(x.size())
const int mod=998244353,MAX=300005,INF=15<<26;

int main(){
    
    std::ifstream in("text.txt");
    std::cin.rdbuf(in.rdbuf());
    cin.tie(0);
    ios::sync_with_stdio(false);
    
    ll N;cin>>N;
    vl A(N+1),B(N+1);
    for(int i=0;i<N;i++){
        ll x;cin>>x;
        A[i+1]=A[i]+x;
    }
    for(int i=0;i<N;i++){
        ll x;cin>>x;
        B[i+1]=B[i]+x;
    }
    double ng=0,ok=1.1e9;
    for(int q=0;q<70;q++){
        double mid=(ok+ng)/2;
        vector<double> S(N+1);
        for(int i=0;i<=N;i++){
            S[i]=A[i]-mid*B[i];
        }
        auto L=S,R=S;
        for(int i=1;i<=N;i++) chmin(L[i],L[i-1]);
        for(int i=N-1;i>=0;i--) chmax(R[i],R[i+1]);
        bool f=false;
        for(int i=0;i<N;i++){
            if(L[i]>=R[i+1]) f=true;
        }
        if(f) ok=mid;
        else ng=mid;
    }
    cout<<fixed<<setprecision(25)<<ok<<endl;
}