#include<stdio.h>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <algorithm>
#include <sstream>
#include <iostream>
#include <string>
#include <stdio.h>

using namespace std;

int main() {

	int N;
	double A[1005];
	cin >> N;
	for (int i = 0; i < N; i++) {
		cin >> A[i];
	}
	sort(A, A+N);
	cout <<(A[(N-1)/2] + A[N/2])/2.0 << endl;
	return 0;
}