#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;

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