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

int main() {
    double n, a, b;
    vector<int> lists;
    cin >> n;
    for (int i=0; i<n; ++i) {
        cin >> a;
        lists.push_back(a);
    }
    sort(lists.begin(), lists.end());
    if (lists.size() % 2 == 0) {
        b = (lists[lists.size()/2] + lists[(lists.size()/2)-1]) / 2.0;
    }else{
        b = lists[lists.size()/2];
    }
    
    cout << b << endl;
    
    
    return 0;
}