#include <bits/stdc++.h>
#define rep(i, a) for (int i = 0; i < (a); i++)
#define rep2(i, a, b) for (int i = (a); i < (b); i++)
#define repr(i, a) for (int i = (a) - 1; i >= 0; i--)
#define repr2(i, a, b) for (int i = (b) - 1; i >= (a); i--)
using namespace std;
typedef long long ll;

int main() {
	int n;
	cin >> n;
	vector<int> a(n);
	rep (i, n) cin >> a[i];
	sort(a.begin(), a.end());
	if (n % 2 == 0) {
		int ans = a[(n - 1) / 2] + a[n / 2];
		if (ans % 2 == 0) {
			cout << ans / 2 << endl;	
		} else {
			cout << ans / 2 << ".5" << endl;
		}
	} else {
		cout << a[n / 2] << endl;
	}
	return 0;
}