#include <bits/stdc++.h>
using namespace std;

int main()
{
    int N;
    double median = 0;
    cin >> N;
    vector<double> A(N);
    for (int i = 0; i < N; ++i){
        cin >> A[i];
    }

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

    // 偶数なら // 
    if (N % 2 == 0){
        median = (A[N/2 - 1] + A[N/2]) / 2;
    }else{ // 奇数なら //
        median = A[N/2];
    }

    cout << median << endl; 
    return 0; 
}