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

int main() {
    int n;
    cin >> n;
    vector<double> a(n);
    for (auto &e : a) cin >> e;
    sort(a.begin(), a.end());
    
    double ans = ((n&1) ? a[n / 2] : (a[n / 2 - 1] + a[n / 2]) / 2.0);
    cout << fixed << setprecision(1) << ans << '\n';
    return 0;
}