import java.util.Scanner;
import java.util.ArrayList;
import java.util.List;
import java.util.Collections;

class Wandbox
{
    public static void main(String[] args)
    {
    	Scanner sc = new Scanner(System.in);
    	
    	List<Integer> list = new ArrayList<>();
    	
    	int n = sc.nextInt();
    	double ans = 0;
    	
    	for (int i = 0; i < n; i++) {
    		
    		list.add(sc.nextInt());
    	} 
    	Collections.sort(list);
    	
    	if (n % 2 == 0) {
    		n /= 2;
    		ans = (double)(list.get(n - 1) + list.get(n)) / 2;
    		System.out.println(ans);
    	} else {
    		n /= 2 ;
    		System.out.println(list.get(n));
    	}
    }
}