#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

int main()
{
    int n, a[1001];
    cin >> n;

    for(int i=0; i<n; i++)
        cin >> a[i];

    sort(a, a+n);

    double ans;
    if(n%2) ans = a[n/2];
    else ans = (double)(a[n/2] + a[n/2-1]) / 2;

    cout << ans << endl;

    return 0;
}