#include <bits/stdc++.h>
using namespace std;

int main() {
    int n;
    cin >> n;
    vector<int> a(n);
    for (int i = 0;i < n; i++) cin >> a[i];
    sort(a.begin(), a.end());
    if (n % 2 == 0) {
        double ans = (a[n/2-1] + a[n/2]) / 2.0;
        cout << setprecision(20) << ans << endl;
    } else {
        cout << a[n/2] << endl;
    }
    return 0;
}