#include<bits/stdc++.h>
#define st first
#define nd second
#define pb push_back
#define eb emplace_back
#define pp pop_back
#define mp make_pair
#define all(x) (x).begin(), (x).end()
using namespace std;
using vi = vector<int>;
using pii = pair<int, int>;
using vii = vector<pii>;
using ll = long long;
using ld = long double;
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
int main(){
	int n;
	cin>>n;
	vector<ll> V(n+1);
	for(int i=1; i<=n; i++){
		cin>>V[i];
		V[i]+=V[i-1];
	}
	priority_queue<pair<ld, pii> > Q;
	ld ans=1e9;
	ld M=V[n]/ld(n);
	while(true){
		vi gdzie(n);
		ld mm=M;
		for(int i=0; i<n; i++){
			int l=1, r=n-i-1;
			while(l<r){
				int m=(l+r+1)>>1;
				if((V[m+i]-V[m-1])/ld(i+1)>M)r=m-1;
				else l=m;
			}
			gdzie[i]=l;
			mm=min(mm, (V[l+i]-V[l-1])/ld(i+1));
		}
		ans=min(ans, M-mm);
		bool czy=1;
		for(int i=0; i<n; i++){
			int l=gdzie[i];
			if(mm==(V[l+i]-V[l-1])/ld(i+1)){
				if(gdzie[i]==n-i-1){
					czy=0;
				}
				else{
					M=max(M, (V[l+i+1]-V[l])/ld(i+1));
				}
			}
		}
		if(!czy)break;
	}
	cout<<fixed<<setprecision(10)<<ans;
}