// No.275 中央値を求めよ
// https://yukicoder.me/problems/no/275
//
#include <iostream>
#include <vector>
#include <regex>
#include <iomanip>
using namespace std;

double solve(vector<int> &numbers, int N);


int main() {
    unsigned int N;
    cin >> N;
    vector<int> numbers(N);
    for (auto i = 0; i < N; i++)
        cin >> numbers[i];

    double ans = solve(numbers, N);
    cout << fixed << setprecision(1) << ans << endl;
}

double solve(vector<int> &numbers, int N) {
    sort(numbers.begin(), numbers.end());
    if (N % 2 == 1) {
        return numbers[N/2];
    } else {
        return (numbers[N/2-1] + numbers[N/2]) / 2.0;
    }
}