#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

int main() {
    int n;
    cin >> n;
    vector<float> a(n);
    for(int i = 0;i < n;i++){
        cin >> a[i];
    }
    sort(a.begin(),a.end());
    int index = (n%2 == 0) ? n/2 -1 : n/2;
    cout << (a[index] + a[n - index -1]) / 2 << endl;
    return 0;
}