#pragma region Macros
#include <bits/stdc++.h>
using namespace std;
template <class T> inline bool chmax(T &a, T b) {
    if(a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T> inline bool chmin(T &a, T b) {
    if(a > b) {
        a = b;
        return 1;
    }
    return 0;
}
#ifdef DEBUG
template <class T, class U>
ostream &operator<<(ostream &os, const pair<T, U> &p) {
    os << '(' << p.first << ',' << p.second << ')';
    return os;
}
template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
    os << '{';
    for(int i = 0; i < (int)v.size(); i++) {
        if(i) { os << ','; }
        os << v[i];
    }
    os << '}';
    return os;
}
void debugg() { cerr << endl; }
template <class T, class... Args>
void debugg(const T &x, const Args &... args) {
    cerr << " " << x;
    debugg(args...);
}
#define debug(...)                                                             \
    cerr << __LINE__ << " [" << #__VA_ARGS__ << "]: ", debugg(__VA_ARGS__)
#define dump(x) cerr << __LINE__ << " " << #x << " = " << (x) << endl
#else
#define debug(...) (void(0))
#define dump(x) (void(0))
#endif

struct Setup {
    Setup() {
        cin.tie(0);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(15);
    }
} __Setup;

using ll = long long;
#define ALL(v) (v).begin(), (v).end()
#define RALL(v) (v).rbegin(), (v).rend()
#define FOR(i, a, b) for(int i = (a); i < int(b); i++)
#define REP(i, n) FOR(i, 0, n)
const int INF = 1 << 30;
const ll LLINF = 1LL << 60;
constexpr int MOD = 1000000007;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, 1, 0, -1};

void Case(int i) { cout << "Case #" << i << ": "; }
#pragma endregion Macros

using D = long double;

int main() {
    int N;
    cin >> N;
    vector<ll> a(N), sum(N+1, 0);
    REP(i, N) cin >> a[i];
    sort(ALL(a));
    REP(i, N) sum[i+1] = sum[i] + a[i];

    D ans = LLINF;

    REP(i, N) {
        // min(A_i, 2x)のsum
        D sum1 = sum[i+1] + a[i] * (N - i - 1);
        // xのsum
        D sum2 = a[i] * N;
        sum2 /= D(2);
        D sum3 = sum[N];
        chmin(ans, ((sum2 - sum1) + sum3) / N);
    }

    cout << ans << endl;
}
#include<cstdio>
#include<algorithm>
#include<vector>
#include<set>
using namespace std;
using ll = long long;
constexpr int N = 1e6 + 5;

int n;
int a[N];
ll sum[N];

int main() {
    scanf("%d", &n);
    for(int i = 1; i <= n; ++i) {
        scanf("%d", &a[i]);
    }
    sort(a + 1, a + 1 + n);
    for(int i = 1; i <= n; ++i) {
        sum[i] = sum[i - 1] + a[i];
    }
    double ret = 1e18;
    for(int i = 1; i <= n; ++i) {
        double x = a[i] / 2.0;
        double tt = 1.0 * sum[n] / n + x;
        tt -= (sum[i] + (n - i) * x * 2) / n;
        ret = min(ret, tt);
    }
    printf("%.8lf", ret);
}