#include <bits/stdc++.h>
using namespace std;
#define int ll
#define ll long long
#define pii pair<int, int>
#define f first
#define s second
#define REP(i,n) for (int i = 0; i<n; ++i)
#define REP1(i,n) for(int i = 1; i<=n; ++i)
#define MX(a,b) a = max(a,b)
#define MN(a,b) a = min(a,b)
#define pb push_back
#define SZ(x) (int)((x).size())
#define ALL(x) (x).begin(),(x).end()
#ifdef BALBIT
#define bug(...) cerr<<"#"<<__LINE__<<" "<<#__VA_ARGS__<<"- ", _do(__VA_ARGS__)
template<typename T> void _do(T && x) {cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T && x, S && ...y) {cerr<<x<<", "; _do(y...);}
#else
#define bug(...)
#define endl '\n'
#endif
const ll inf = 0x3f3f3f3f3f3f3f3f;
const int maxn = 2e5+5;
int a[maxn], ps[maxn];
vector<ll> yoi;
signed main(){
ios::sync_with_stdio(0), cin.tie(0);
bug(1,2);
int n; cin>>n;
REP1(i,n) {
cin>>a[i];
ps[i] = ps[i-1] + a[i];
}
vector<pair<double, double> > po;
double cen = ps[n] / (double)(n);
double rbound = cen;
{
int x = 0;
for (int i = n; i>=1;--i) {
while (x+i<n && (ps[x+i]-ps[x]) * (__int128) n < ps[n] * (__int128)i) {
++x;
}
if (i == n) {
po.pb({cen, inf});
}else{
assert(x>0);
double prv = (ps[x+i-1] - ps[x-1])/(double)i;
double ha = (ps[x+i] - ps[x])/(double)i;
po.pb({prv, ha}); po.pb({ha, inf});
}
}
}
sort(ALL(po));
double re = inf;
for(auto yo : po) {
MN(re,rbound - yo.f);
MX(rbound, yo.s);
if(rbound >= inf -1) break;
}
cout<<fixed<<setprecision(12)<<re<<endl;
}
