#include<iostream>
#include<stdio.h>
#include<string>
#include<algorithm>
using namespace std;
int main()
{
	int n;
	cin >> n;
	int a[1000];
	for (int i = 0; i < n; i++)
	{
		cin >> a[i];
	}
	sort(a, a + n);
	double ans;
	if (n % 2 == 0) {
		ans = (a[n / 2 - 1] + a[n / 2]) / 2.0;
	}
	else ans = a[n / 2];
	printf("%1f\n", ans);
	return 0;
}