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

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		// Nの入力
		int N = sc.nextInt();
		
		// viをPriorityQueueに格納
		PriorityQueue<Double> pq = new PriorityQueue<> ();
		for (int i = 0; i < N; i++) {
			pq.add(sc.nextDouble());
		}
		
		for (int i = 0; i < N-1; i++) {
			double x = pq.poll();
			double y = pq.poll();
			pq.add((x+y)/2);
		}
		
		System.out.println(pq.poll());
		
		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);
		
		// Nの入力
		int N = sc.nextInt();
		
		// viをPriorityQueueに格納
		PriorityQueue<Double> pq = new PriorityQueue<> ();
		for (int i = 0; i < N; i++) {
			pq.add(sc.nextDouble());
		}
		
		for (int i = 0; i < N-1; i++) {
			double x = pq.poll();
			double y = pq.poll();
			pq.add((x+y)/2);
		}
		
		System.out.println(pq.poll());
		
		sc.close();
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		// Nの入力
		int N = sc.nextInt();
		
		// viをPriorityQueueに格納
		PriorityQueue<Double> pq = new PriorityQueue<> ();
		for (int i = 0; i < N; i++) {
			pq.add(sc.nextDouble());
		}
		
		for (int i = 0; i < N-1; i++) {
			double x = pq.poll();
			double y = pq.poll();
			pq.add((x+y)/2);
		}
		
		System.out.println(pq.poll());
		
		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);
		
		// Nの入力
		int N = sc.nextInt();
		
		// viをPriorityQueueに格納
		PriorityQueue<Double> pq = new PriorityQueue<> ();
		for (int i = 0; i < N; i++) {
			pq.add(sc.nextDouble());
		}
		
		for (int i = 0; i < N-1; i++) {
			double x = pq.poll();
			double y = pq.poll();
			pq.add((x+y)/2);
		}
		
		System.out.println(pq.poll());
		
		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<> (); pq new PriorityQueue<> () 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 for (int i = 0; i < N-1; i++) {
			double x = pq.poll();
			double y = pq.poll();
			pq.add((x+y)/2);
		} int i = 0; int i = 0; i 0 i < N-1 i N-1 N 1 i++ i++ i {
			double x = pq.poll();
			double y = pq.poll();
			pq.add((x+y)/2);
		} {
			double x = pq.poll();
			double y = pq.poll();
			pq.add((x+y)/2);
		} double x = pq.poll(); x pq.poll() pq.poll pq double y = pq.poll(); y pq.poll() pq.poll pq pq.add((x+y)/2) pq.add pq (x+y)/2 (x+y) x y 2 System.out.println(pq.poll()) System.out.println System.out System System.out pq.poll() pq.poll pq sc.close() sc.close sc String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		// Nの入力
		int N = sc.nextInt();
		
		// viをPriorityQueueに格納
		PriorityQueue<Double> pq = new PriorityQueue<> ();
		for (int i = 0; i < N; i++) {
			pq.add(sc.nextDouble());
		}
		
		for (int i = 0; i < N-1; i++) {
			double x = pq.poll();
			double y = pq.poll();
			pq.add((x+y)/2);
		}
		
		System.out.println(pq.poll());
		
		sc.close();
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		// Nの入力
		int N = sc.nextInt();
		
		// viをPriorityQueueに格納
		PriorityQueue<Double> pq = new PriorityQueue<> ();
		for (int i = 0; i < N; i++) {
			pq.add(sc.nextDouble());
		}
		
		for (int i = 0; i < N-1; i++) {
			double x = pq.poll();
			double y = pq.poll();
			pq.add((x+y)/2);
		}
		
		System.out.println(pq.poll());
		
		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);
		
		// Nの入力
		int N = sc.nextInt();
		
		// viをPriorityQueueに格納
		PriorityQueue<Double> pq = new PriorityQueue<> ();
		for (int i = 0; i < N; i++) {
			pq.add(sc.nextDouble());
		}
		
		for (int i = 0; i < N-1; i++) {
			double x = pq.poll();
			double y = pq.poll();
			pq.add((x+y)/2);
		}
		
		System.out.println(pq.poll());
		
		sc.close();
	}
}
