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

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int ans[] = new int[n];

		for (int i = 0; i < n; i++) {
			ans[i] = sc.nextInt();
		}
		Arrays.sort(ans);
		if (n % 2 == 0) { // 奇数
			System.out.println((ans[(n / 2) - 1] + ans[n / 2]) / 2.0);
		} else { // 偶数
			System.out.println(ans[n / 2]);
		}
	}
}