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> queue = new PriorityQueue<>();
    for (int i = 0; i < n; i++) {
      queue.add(sc.nextDouble());
    }
    while (queue.size() > 1) {
      double item1 = queue.poll();
      double item2 = queue.poll();
      queue.add((item1 + item2) / 2);
    }
    System.out.println(queue.peek());
  }
} 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> queue = new PriorityQueue<>();
    for (int i = 0; i < n; i++) {
      queue.add(sc.nextDouble());
    }
    while (queue.size() > 1) {
      double item1 = queue.poll();
      double item2 = queue.poll();
      queue.add((item1 + item2) / 2);
    }
    System.out.println(queue.peek());
  }
} 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 item1 = queue.poll();
      double item2 = queue.poll();
      queue.add((item1 + item2) / 2);
    }
    System.out.println(queue.peek());
  } 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 item1 = queue.poll();
      double item2 = queue.poll();
      queue.add((item1 + item2) / 2);
    }
    System.out.println(queue.peek());
  } 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 item1 = queue.poll();
      double item2 = queue.poll();
      queue.add((item1 + item2) / 2);
    } queue.size() > 1 queue.size() queue.size queue 1 {
      double item1 = queue.poll();
      double item2 = queue.poll();
      queue.add((item1 + item2) / 2);
    } double item1 = queue.poll(); item1 queue.poll() queue.poll queue double item2 = queue.poll(); item2 queue.poll() queue.poll queue queue.add((item1 + item2) / 2) queue.add queue (item1 + item2) / 2 (item1 + item2) item1 item2 2 System.out.println(queue.peek()) System.out.println System.out System System.out queue.peek() queue.peek 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 item1 = queue.poll();
      double item2 = queue.poll();
      queue.add((item1 + item2) / 2);
    }
    System.out.println(queue.peek());
  }
} 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 item1 = queue.poll();
      double item2 = queue.poll();
      queue.add((item1 + item2) / 2);
    }
    System.out.println(queue.peek());
  }
} 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> queue = new PriorityQueue<>();
    for (int i = 0; i < n; i++) {
      queue.add(sc.nextDouble());
    }
    while (queue.size() > 1) {
      double item1 = queue.poll();
      double item2 = queue.poll();
      queue.add((item1 + item2) / 2);
    }
    System.out.println(queue.peek());
  }
}