#include <iostream>		//cin, cout
#include <vector>		//vector
#include <algorithm>	//sort,min,max,count
#include <string>		//string,getline, to_string
#include <cstdlib>		//abs(int)

using namespace std;

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 {
		double ans = (A[N / 2] + A[N / 2 - 1]) / 2.0;
		cout << ans << endl;
	}

	return 0;

}