#include <iostream>
#include <vector>
#include <algorithm>
#include <stdio.h>

using namespace std;

int main(void)
{
	int N;
	vector<int> A;
	cin >> N;
	for (int i = 0; i < N; i++) {
		int a;
		cin >> a;
		A.push_back(a);
	}
	sort(A.begin(), A.end());

	const int len = A.size();
	double ans;
	if (len & 1) {
		ans = A[len/2];
	} else {
		ans = (double)(A[(len-1)/2] + A[(len-1)/2+1]) / 2.;
	}
	printf("%.1lf\n", ans);
}