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

int main(){
  int n;
  cin>>n;
  vector<double> a(n),b(n);
  for (int i=0;i<n;i++) cin>>a[i];
  for (int i=0;i<n;i++) cin>>b[i];
  double l=0,r=1e9;
  int t=100;
  while (t--){
    double mid=(l+r)/2;
    vector<double> s(n+1);
    for (int i=0;i<n;i++) s[i+1]=s[i]+(a[i]-b[i]*mid);
    vector<double> ms=s;
    for (int i=n-1;i>=0;i--) ms[i]=max(ms[i],ms[i+1]);
    double mins=0;
    bool f=true;
    for (int i=0;i<n;i++){
      mins=min(mins,s[i]);
      if (ms[i+1]-mins<0) f=false;
    }
    if (f) l=mid;
    else r=mid;
  }
  cout<<fixed<<setprecision(10);
  cout<<l<<endl;
}