import java.util.*;
import java.io.*;

public class Main {

	public void go() {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

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

		while (queue.size() != 1) {
			Double a = queue.poll();
			Double b = queue.poll();
			queue.add((a + b) / 2);
		}

		System.out.println(queue.poll());

	}

	public static void main(String[] args) throws IOException {

		Main m = new Main();
		m.go();
	}

} import java.util.*; util.* java import java.io.*; io.* java public class Main {

	public void go() {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

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

		while (queue.size() != 1) {
			Double a = queue.poll();
			Double b = queue.poll();
			queue.add((a + b) / 2);
		}

		System.out.println(queue.poll());

	}

	public static void main(String[] args) throws IOException {

		Main m = new Main();
		m.go();
	}

} Main public void go() {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

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

		while (queue.size() != 1) {
			Double a = queue.poll();
			Double b = queue.poll();
			queue.add((a + b) / 2);
		}

		System.out.println(queue.poll());

	} go {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

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

		while (queue.size() != 1) {
			Double a = queue.poll();
			Double b = queue.poll();
			queue.add((a + b) / 2);
		}

		System.out.println(queue.poll());

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int x = sc.nextInt(); x sc.nextInt() sc.nextInt sc PriorityQueue<Double> queue = new PriorityQueue<>(); queue new PriorityQueue<>() for (int i = 0; i < x; i++) {
			queue.add(sc.nextDouble());
		} int i = 0; int i = 0; i 0 i < x i x i++ i++ i {
			queue.add(sc.nextDouble());
		} {
			queue.add(sc.nextDouble());
		} queue.add(sc.nextDouble()) queue.add queue sc.nextDouble() sc.nextDouble sc while (queue.size() != 1) {
			Double a = queue.poll();
			Double b = queue.poll();
			queue.add((a + b) / 2);
		} queue.size() != 1 queue.size() queue.size queue 1 {
			Double a = queue.poll();
			Double b = queue.poll();
			queue.add((a + b) / 2);
		} Double a = queue.poll(); a queue.poll() queue.poll queue Double b = queue.poll(); b queue.poll() queue.poll queue queue.add((a + b) / 2) queue.add queue (a + b) / 2 (a + b) a b 2 System.out.println(queue.poll()) System.out.println System.out System System.out queue.poll() queue.poll queue public static void main(String[] args) throws IOException {

		Main m = new Main();
		m.go();
	} main {

		Main m = new Main();
		m.go();
	} Main m = new Main(); m new Main() m.go() m.go m String[] args args public class Main {

	public void go() {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

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

		while (queue.size() != 1) {
			Double a = queue.poll();
			Double b = queue.poll();
			queue.add((a + b) / 2);
		}

		System.out.println(queue.poll());

	}

	public static void main(String[] args) throws IOException {

		Main m = new Main();
		m.go();
	}

} public class Main {

	public void go() {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

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

		while (queue.size() != 1) {
			Double a = queue.poll();
			Double b = queue.poll();
			queue.add((a + b) / 2);
		}

		System.out.println(queue.poll());

	}

	public static void main(String[] args) throws IOException {

		Main m = new Main();
		m.go();
	}

} Main
import java.util.*;
import java.io.*;

public class Main {

	public void go() {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

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

		while (queue.size() != 1) {
			Double a = queue.poll();
			Double b = queue.poll();
			queue.add((a + b) / 2);
		}

		System.out.println(queue.poll());

	}

	public static void main(String[] args) throws IOException {

		Main m = new Main();
		m.go();
	}

}
