#include <bits/stdc++.h>
using namespace std;
#define int long long
using ii = pair<int, int>;
using tp = tuple<long double, int, int>;
const int N = 2e5 + 5;
const long long INF = 1e18;
int n, a[N];
namespace sub3{
long double value[5005][5005], res = INF;
void solve(){
for(int i = 1; i <= n; i++){
int sum = 0;
for(int j = i; j <= n; j++){
sum += a[j];
value[i][j] = (long double)sum / (j - i + 1);
}
}
priority_queue<tp, vector<tp>, greater<>> pq;
for(int i = 1; i <= n; i++)
for(int j = i; j <= n; j++) pq.push({value[i][j], i, j});
multiset<long double> s;
for(int i = 1; i <= n; i++) s.insert(value[1][i]);
while(pq.size()){
auto [mn, l, r] = pq.top(); pq.pop();
res = min(res, *s.rbegin() - mn);
s.erase(s.find(mn));
s.insert(value[l + 1][r + 1]);
if(l == 1 && r == n) break;
}
cout << setprecision(12) << fixed << res << "\n";
}
}
int32_t main(){
cin.tie(0)->sync_with_stdio(0);
cin >> n;
for(int i = 1; i <= n; i++) cin >> a[i];
sub3::solve();
return 0;
}
