#include <iostream>
#include <string>
#define N 1000
using namespace std;
void sort(int n, int a[]) {
    int i, j, tmp;
    for (i=0; i<=n-2; i++) {
        for (j=i+1; j<n; j++) {
            if (a[i] > a[j]) {
                tmp = a[i];
                a[i] = a[j];
                a[j] = tmp;
            }
        }
    }
}
int main() {
    int i, n, arr[N], j;
    cin >> n;
    for (i=0; i<n; i++) cin >> arr[i];
    sort(n, arr);
    if (n % 2 == 0) {
        j = n / 2;
        cout << (double)(arr[j-1] + arr[j]) / 2.0 << endl;
    } else {
        j = n / 2;
        cout << arr[j];
    }
    return 0;
}