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

int main() {
    int n;
    cin >> n;
    vector<int> a(n);
    for(int i=0; i<n; i++) cin >> a[i];
    sort(a.begin(),a.end());

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

    cout << ans << endl;
    return 0;
}