import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {

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

		int n = sc.nextInt();

		PriorityQueue<Double> pq = new PriorityQueue<Double>();
		for (int i = 0; i < n; i++) {
			pq.add(sc.nextDouble());
		}

		while (pq.size() > 1) {
			pq.add((pq.poll() + pq.poll()) / 2);
		}
		System.out.println(pq.peek());
		sc.close();
	}

} import java.util.PriorityQueue; PriorityQueue java.util import java.util.Scanner; Scanner java.util public class Main {

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

		int n = sc.nextInt();

		PriorityQueue<Double> pq = new PriorityQueue<Double>();
		for (int i = 0; i < n; i++) {
			pq.add(sc.nextDouble());
		}

		while (pq.size() > 1) {
			pq.add((pq.poll() + pq.poll()) / 2);
		}
		System.out.println(pq.peek());
		sc.close();
	}

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

		int n = sc.nextInt();

		PriorityQueue<Double> pq = new PriorityQueue<Double>();
		for (int i = 0; i < n; i++) {
			pq.add(sc.nextDouble());
		}

		while (pq.size() > 1) {
			pq.add((pq.poll() + pq.poll()) / 2);
		}
		System.out.println(pq.peek());
		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();

		PriorityQueue<Double> pq = new PriorityQueue<Double>();
		for (int i = 0; i < n; i++) {
			pq.add(sc.nextDouble());
		}

		while (pq.size() > 1) {
			pq.add((pq.poll() + pq.poll()) / 2);
		}
		System.out.println(pq.peek());
		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc PriorityQueue<Double> pq = new PriorityQueue<Double>(); pq new PriorityQueue<Double>() for (int i = 0; i < n; i++) {
			pq.add(sc.nextDouble());
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			pq.add(sc.nextDouble());
		} {
			pq.add(sc.nextDouble());
		} pq.add(sc.nextDouble()) pq.add pq sc.nextDouble() sc.nextDouble sc while (pq.size() > 1) {
			pq.add((pq.poll() + pq.poll()) / 2);
		} pq.size() > 1 pq.size() pq.size pq 1 {
			pq.add((pq.poll() + pq.poll()) / 2);
		} pq.add((pq.poll() + pq.poll()) / 2) pq.add pq (pq.poll() + pq.poll()) / 2 (pq.poll() + pq.poll()) pq.poll() pq.poll pq pq.poll() pq.poll pq 2 System.out.println(pq.peek()) System.out.println System.out System System.out pq.peek() pq.peek pq sc.close() sc.close sc String[] args args public class Main {

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

		int n = sc.nextInt();

		PriorityQueue<Double> pq = new PriorityQueue<Double>();
		for (int i = 0; i < n; i++) {
			pq.add(sc.nextDouble());
		}

		while (pq.size() > 1) {
			pq.add((pq.poll() + pq.poll()) / 2);
		}
		System.out.println(pq.peek());
		sc.close();
	}

} public class Main {

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

		int n = sc.nextInt();

		PriorityQueue<Double> pq = new PriorityQueue<Double>();
		for (int i = 0; i < n; i++) {
			pq.add(sc.nextDouble());
		}

		while (pq.size() > 1) {
			pq.add((pq.poll() + pq.poll()) / 2);
		}
		System.out.println(pq.peek());
		sc.close();
	}

} Main
import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {

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

		int n = sc.nextInt();

		PriorityQueue<Double> pq = new PriorityQueue<Double>();
		for (int i = 0; i < n; i++) {
			pq.add(sc.nextDouble());
		}

		while (pq.size() > 1) {
			pq.add((pq.poll() + pq.poll()) / 2);
		}
		System.out.println(pq.peek());
		sc.close();
	}

}
