//https://ncode.syosetu.com/n4830bu/275/
#include <bits/stdc++.h>
using namespace std;

int main() {
    int N;
    cin >> N;
    vector<double> A(N);
    for (auto&& a : A) {
        cin >> a;
    }
    sort(begin(A), end(A));
    if (N % 2)
        cout << A[N / 2] << endl;
    else
        cout << (A[N / 2 - 1] + A[N / 2]) / 2.0 << endl;
}