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

public class No275 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		ArrayList<Double> A = new ArrayList<Double>();

		for (double i = 1; i <= N; i++) {
			A.add(sc.nextDouble());
		}

		Collections.sort(A);

		if (A.size() % 2 == 0) {
			double d = ((A.get(A.size() / 2)) + (A.get((A.size() - 1) / 2))) / 2;
			System.out.println(d);
		} else {
			System.out.println(A.get(A.size() / 2));
		}
	}
}