#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-8;
int INF = INT_MAX / 2;

int main() {
	int N; cin >> N;
	vector<int> A(N);
	for (int i = 0; i < N; i++)
		cin >> A[i];
	sort(A.begin(), A.end());
	if (N % 2 == 1)
		cout << A[N / 2] << endl;
	else {
		int sum = A[N / 2] + A[N / 2 - 1];
		if (sum % 2 == 0) cout << sum / 2 << endl;
		else cout << sum / 2 << ".5" << endl;
	}
}