import java.util.Arrays;
import java.util.Scanner;

public class Test {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int num = sc.nextInt();
		int[] n = new int[num];
		for (int i = 0; i < num; i++) {
			n[i] = sc.nextInt();
		}
		Arrays.sort(n);
		if (num % 2 == 0) {
			System.out.println((double) (n[num / 2] + n[num / 2 - 1]) / 2);
		} else {
			System.out.println(n[num / 2]);
		}
	}
}