#include <bits/stdc++.h>
using namespace std;
template <typename T> using vec = vector<T>;
template <typename T> using vvec = vector<vector<T>>;

constexpr int64_t mpow(int64_t a, int64_t b, int64_t mod = 1000000007) {
    if (b <= 0) { return 1; } if (b == 1) { return a % mod; } if (b == 2) { return (a * a) % mod; }
    return (max(a * (b & 1), (int64_t)1) * mpow(mpow(a, b / 2, mod), 2, mod)) % mod;
}
constexpr int64_t mdiv(int64_t a, int64_t b, int64_t mod = 1000000007) {
    return (a * mpow(b, mod - 2, mod)) % mod;
}

int main() {
    cout << fixed << setprecision(1);
    int n; cin >> n;
    vec<int> a(n);
    for (auto &e : a) cin >> e;
    sort(a.begin(), a.end());

    double ans;
    if (!(n & 1) && 1 < n) {
        ans = (a[n / 2] + a[n / 2 - 1]) / 2.0;
    }
    else {
        ans = a[n / 2];
    }

    cout << ans << endl;
}