#include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < n; i++)
using namespace std;

int main() {
    int n;
    cin >> n;
    vector<int> num(n);
    rep(i, n) cin >> num.at(i);
    sort(num.begin(), num.end());
    double ans;
    if(n % 2 == 0) ans = (num.at(n / 2 - 1) + num.at(n / 2)) / 2.0;
    else ans = num.at(n / 2);
    cout << fixed << setprecision(1) << ans << endl;
}