import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;
public class No0275 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		double ave = 0;
		List<Double> list = new ArrayList<Double>();
		for(int i=0; i<n; i++){
			list.add(sc.nextDouble());
		}
		Collections.sort(list);
		if(n%2 == 1){
			ave = list.get(n/2);
		}else {
			ave = (list.get(n/2 - 1) + list.get(n/2)) / 2;
		}
		System.out.println(ave);
	}
}