#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int mod = 1e9 + 7;
const int inf = (1 << 30) - 1;
const ll infll = (1LL << 61) - 1;

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

    sort(a.begin(), a.end());
    if (N % 2 == 0)
        cout << (a[N / 2] + a[(N - 1) / 2]) / 2. << endl;
    else
        cout << a[N / 2] << endl;
}