#include <bits/stdc++.h>

using namespace std;

// using mint = long double;
// using mint = modint998244353;
// using mint = modint1000000007;

typedef long long ll;
typedef pair<ll, ll> P;
typedef pair<ll, P> T;
typedef pair<ll, vector<ll>> Pd;

const ll INF = 1e18;
const ll fact_table = 820000;

priority_queue<ll> pql;
priority_queue<P> pqp;
// big priority queue
priority_queue<ll, vector<ll>, greater<ll>> pqls;
priority_queue<P, vector<P>, greater<P>> pqps;

// small priority queue
// top pop

ll dx[8] = {1, 0, -1, 0, 1, 1, -1, -1};
ll dy[8] = {0, 1, 0, -1, -1, 1, 1, -1};
//↓,→,↑,←

#define p(x) cout << x << "\n";
#define el cout << "\n";
#define pe(x) cout << x << " ";
#define ps(x) cout << fixed << setprecision(25) << x << endl;
#define pu(x) cout << (x);
#define pb push_back
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define pc(x) cout << x << ",";
#define rep(i, n) for (ll i = 0; i < (n); i++)
#define rep2(i, a, b) for (ll i = a; i <= (b); i++)
#define rep3(i, a, b) for (ll i = a; i >= (b); i--)
#define all(c) begin(c), end(c)
#define sorti(v) sort(all(v))
#define sortd(v)                                                               \
    sort(all(v));                                                              \
    reverse(all(v));
#define SUM(v) accumulate(all(v), 0LL)
#define MIN(v) *min_element(all(v))
#define MAX(v) *max_element(all(v))

typedef vector<ll> vec;
typedef vector<vector<ll>> mat;

// vec v(n) -> 長さnのベクトルを宣言
// mat dp(h, vec(w)) -> h * w の行列を宣言

const ll mod = 1000000007ll;
// const ll mod = 998244353ll;

ll mypow(ll a, ll b, ll m = mod) {
    ll x = 1;
    while (b) {
        while (!(b & 1)) {
            (a *= a) %= m;
            b >>= 1;
        }
        (x *= a) %= m;
        b--;
    }
    return x;
}
vec rv(ll read) {
    vec res(read);
    for (int i = 0; i < read; i++) {
        cin >> res[i];
    }
    return res;
}
/*
ll fact[fact_table + 5], rfact[fact_table + 5];

void c3_init() {
    fact[0] = rfact[0] = 1;
    for (ll i = 1; i <= fact_table; i++) {
        fact[i] = (fact[i - 1] * i) % mod;
    }
    rfact[fact_table] = mypow(fact[fact_table], mod - 2, mod);
    for (ll i = fact_table; i >= 1; i--) {
        rfact[i - 1] = rfact[i] * i;
        rfact[i - 1] %= mod;
    }
    return;
}

ll c3(ll n, ll r) {
    return (((fact[n] * rfact[r]) % mod) * rfact[n - r]) % mod;
}
*/

bool icpc = false;
bool multicase = false;

ll n;
ll x[100005];
ll dp[100005];

bool solve() {
    cin >> n;
    vec v = rv(n);
    sorti(v);
    ll mid = v[(n + 1) / 2 - 1];

    ll sum2 = mid * n;
    sum2 += SUM(v) * 2ll;
    for (auto e : v) {
        sum2 -= min(e, mid) * 2ll;
    }

    long double ans = sum2 / 2.0;
    ans /= n;
    ps(ans);

    return true;
}
/*







*/

int main() {
    // ios::sync_with_stdio(false);
    // cin.tie(nullptr);
    if (icpc) {
        while (solve())
            ;
        return 0;
    }
    ll q, testcase = 1;
    if (multicase) {
        cin >> q;
    } else {
        q = 1;
    }
    while (q--) {
        // cout << "Case #" << testcase << ": ";
        solve();
        testcase++;
    }

    // solve();
    return 0;
}
#include <iostream>
#include <vector>
//#include <string>
#include <algorithm>
//#include <math.h>
//#include <queue>
//#include <stack>
//#include <iomanip>

// sometimes used
//#include <set>
//#include <map>
//#include <numeric>
//#include <list>
//#include <deque>
//#include <unordered_map>

typedef long long LL;
//typedef long double LD;
using namespace std;
 
//#define MOD 1000000007
//#define MOD 998244353
//#define MAX 200100
//#define NIL -1
//#define INFTY 1000000000000000000

int main(){
    LL n;
    cin >> n;
    vector<LL> a(n);
    for(LL i=0; i<n; i++){
        cin >> a[i];
    }

    sort(a.begin(),a.end());
    while(a[0]!=a[n-1]){
        for(LL i=1; i<n; i++){
            if(a[i]%a[0]==0){
                a[i]=a[0];
            }else{
                a[i]=a[i]-(a[i]/a[0])*a[0];
            }
        }
        sort(a.begin(),a.end());
    }

    cout << a[0] << endl;

    return 0;
}