#include"bits/stdc++.h"
using namespace std;
using ll = long long;
using ld = long double;
#define rep(i,m,n) for(ll i=(ll)m;i<(ll)n;i++)
#define Endl endl
#define pr(i,j) make_pair(i,j) 
const ll mod = 998244353;
const ll inf = 5e18;
const ld pi = 3.14159265358979;
int main() {
	ll n;
	cin >> n;
	vector<ld>a(n);
	rep(i, 0, n)cin >> a[i];
	sort(a.begin(), a.end());
	if (n % 2 == 1) {
		cout << setprecision(15) << fixed << (a[(n - 1) / 2]) << endl;
	}
	else {
		ld med = (a[n / 2 - 1] + a[n / 2]) / 2.0;
		cout << setprecision(15) << fixed << med << endl;
	}
}