// WA 3 1306 Timus test

# include <iostream>
# include <set>
# include <algorithm>
# include <iomanip>

using namespace std;

int main() {
    int32_t n;
    int32_t cur_n = 0;
    set<int32_t> m;
    cin >> n;
    for (size_t i = 0; i < n; i++) {
        int32_t a;
        cin >> a;
        m.insert(a);
        cur_n++;
        if (cur_n > 150000) {
            m.erase(m.begin());
            m.erase(m.rbegin());
            cur_n -= 2;
        }
    }

    if (cur_n % 2 == 0) {
        auto it1 = m.begin();
        advance(it1, cur_n / 2 - 1);
        auto it2 = m.begin();
        advance(it2, cur_n / 2);
        int64_t res = (int64_t)*it1 + (int64_t)*it2;
        cout << fixed << setprecision(1) << (double)res / 2.0;
    }
    else {
        auto it1 = m.begin();
        advance(it1, cur_n / 2);
        cout << *it1;
    }
}