#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

int main() {
	int N;
	cin >> N;
	
	int A[N];
	for(int i=0; i<N;i++) cin>> A[i];
	sort(A,A+N);
	double ans;
	if((N%2)==1) {
		int j = N/2 + 1;
		ans = A[j];
	} else {
		int j = N/2;
		ans =(double) (A[j-1]+A[j]) / 2;
	}
	cout << ans << '\n';
	return 0;
}