#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int main() {
    int n; cin >> n;
    int a[n];
    for (int i = 0; i < n; i++) cin >> a[i];
    sort(a,a+n);
    double ans;
    if (n % 2 == 0) ans = (a[n/2-1] + a[n/2]) / 2.0;
    else ans = a[n/2];
    cout << ans << endl;
    return 0;
}