#include<iostream>
#include<string>
#include<cstring>
#include<complex>
#include<vector>
#include<algorithm>
#include<cstdlib>
#include<cmath>
#include<iomanip>
using namespace std;

#define REP(i, j) for (int i = 0; i < (int)j; ++i)
#define FOR(i, j, k) for (int i = (int)j; i < (int)k; ++i)
#define SORT(v) sort(v.begin(), v.end())
#define REVERSE(v) reverse(v.begin(), v.end())
typedef complex<double> P;
typedef vector<int> VI;
typedef long long LL;
typedef pair<int,int> PII;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int n;
	cin >> n;
	VI a;
	REP(i,n) {
		int ai;
		cin >> ai;
		a.push_back(ai);
	}
	SORT(a);

	if (n % 2) cout << a[n/2] << endl;
	else {
		double ans = (a[n/2-1] + a[n/2]) / 2.0;
		cout << ans << endl;
	}

	return 0;
}