#include <iostream>
#include <vector>
#include <algorithm>
#include <iomanip>

#define REP(i, a, b) for (int i = int(a); i < int(b); i++)

using namespace std;

typedef long long int lli;

int main() {
    int N;
    cin >> N;
    vector<int> v(N);
    REP (i, 0, N) cin >> v[i];
    sort(v.begin(), v.end());
    cout << fixed << setprecision(10) << (N % 2 ? v[N / 2] : (v[N / 2] + v[N / 2 - 1]) / 2.0) << endl;
    return 0;
}