#include <bits/stdc++.h>
using namespace std;
int n, a[1009];
int main() {
	cin >> n;
	for(int i = 0; i < n; i++) cin >> a[i];
	sort(a, a + n);
	if(n % 2 == 1) cout << a[n / 2] << endl;
	else cout << fixed << setprecision(15) << (a[n / 2 - 1] + a[n / 2]) / 2.0 << endl;
	return 0;
}