#include <iostream>
#include <algorithm>

using namespace std;

int main() {
	
	int n;
	cin >> n;
	double a[n];
	for(int i = 0; i < n; i++) cin >> a[i];
	sort(a,a + n);
	
	if(n % 2 == 1){
	    cout << a[n / 2];
	    
	}
	else {
		
		double d = (a[n / 2] + a[n / 2 - 1]) / 2;
		cout << d;
		
	}
	
	
}