#include<iostream>
#include<algorithm>
using namespace std;
int main(void)
{
	int i, n, pa[1010];
	double ans;

	cin >> n;
	for (i = 0; i < n; i++)
		cin >> pa[i];
	sort(pa, pa + n);
	if (n % 2 == 1)
		ans = pa[n / 2];
	else {
		ans = (double)(pa[n / 2 - 1] + pa[n / 2]) / 2;
	}

	cout << ans << endl;

	return 0;
}