#include <bits/stdc++.h>

#define REP(i,l,u) for(int (i)=(int)(l);(i)<(int)(u);++(i))

using namespace std;

typedef int64_t ll;

const int INF = 1e8;
const double EPS = 1e-10;

int main() {
    ios_base::sync_with_stdio(false);
    int N;
    cin >> N;
    vector<int> A(N);
    REP(i, 0, N) {
        cin >> A[i];
    }

    sort(A.begin(), A.end());

    if(N % 2 == 0) {
        int k = (N / 2) - 1;
        cout << 1.0*(A[k]+A[k+1])/2.00 << endl;
    } else {
        cout << A[N/2] << endl;
    }
}