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

int main()
{
    int N;
    int A[1010]; //多めに
    cin >> N;
    for (int i = 0; i < N; i++)
    {
        cin >> A[i];
    }
    sort(A, A + N);
    if (N % 2 == 0)
    {
        cout << A[N / 2] << endl;
    }
    else
    {
        cout << (A[N / 2] + A[N / 2 + 1]) / 2.0 << endl;
    }
    return 0;
}