#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for (int (i)=(0);(i)<(int)(n);++(i))
using ll = long long;
using P = pair<int, int>;
using namespace std;

int main() {
    int N;
    cin >> N;
    vector<int> A(N);
    rep(i, N) cin >> A[i];
    sort(A.begin(), A.end());
    if (N%2) {
        cout << A[A.size()/2] << endl;
    }
    else {
        double tmp = A[A.size()/2] + A[A.size()/2-1];
        printf("%.10f\n", tmp/2.0);
    }
    return 0;
}