import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		PriorityQueue<Double> queue = new PriorityQueue<>();
		for (int i = 0; i < n; 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());
	}
} import java.util.*; util.* java public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		PriorityQueue<Double> queue = new PriorityQueue<>();
		for (int i = 0; i < n; 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());
	}
} Main public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		PriorityQueue<Double> queue = new PriorityQueue<>();
		for (int i = 0; i < n; 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());
	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		PriorityQueue<Double> queue = new PriorityQueue<>();
		for (int i = 0; i < n; 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 n = sc.nextInt(); n sc.nextInt() sc.nextInt sc PriorityQueue<Double> queue = new PriorityQueue<>(); queue new PriorityQueue<>() for (int i = 0; i < n; i++) {
		    queue.add(sc.nextDouble());
		} int i = 0; int i = 0; i 0 i < n i n 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 String[] args args public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		PriorityQueue<Double> queue = new PriorityQueue<>();
		for (int i = 0; i < n; 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 class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		PriorityQueue<Double> queue = new PriorityQueue<>();
		for (int i = 0; i < n; 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());
	}
} Main
import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		PriorityQueue<Double> queue = new PriorityQueue<>();
		for (int i = 0; i < n; 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());
	}
}
