#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
int main() {
    int n;
    cin >> n;
    vector<double> d(n);
    for (int i = 0; i < n; i++) {
        cin >> d[i];
    }
    sort(d.begin(), d.end());
    if (n % 2 == 0) {
        cout << (d[n / 2] + d[n / 2 - 1]) / 2 << endl;
    } else {
        cout << d[n / 2] << endl;
    }
    return 0;
}