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

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

    int N = scanner.nextInt();
    PriorityQueue<Double> pq = new PriorityQueue<>();
    for (int i = 0; i < N; i++) {
      double v = scanner.nextInt();
      pq.add(v);
    }

    while (pq.size() > 1) {
      double a = pq.poll();
      double b = pq.poll();
      pq.add((a + b) * 0.5d);
    }

    System.out.println(pq.poll());
  }
} import java.util.PriorityQueue; PriorityQueue java.util import java.util.Scanner; Scanner java.util public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    int N = scanner.nextInt();
    PriorityQueue<Double> pq = new PriorityQueue<>();
    for (int i = 0; i < N; i++) {
      double v = scanner.nextInt();
      pq.add(v);
    }

    while (pq.size() > 1) {
      double a = pq.poll();
      double b = pq.poll();
      pq.add((a + b) * 0.5d);
    }

    System.out.println(pq.poll());
  }
} Main public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    int N = scanner.nextInt();
    PriorityQueue<Double> pq = new PriorityQueue<>();
    for (int i = 0; i < N; i++) {
      double v = scanner.nextInt();
      pq.add(v);
    }

    while (pq.size() > 1) {
      double a = pq.poll();
      double b = pq.poll();
      pq.add((a + b) * 0.5d);
    }

    System.out.println(pq.poll());
  } main {
    Scanner scanner = new Scanner(System.in);

    int N = scanner.nextInt();
    PriorityQueue<Double> pq = new PriorityQueue<>();
    for (int i = 0; i < N; i++) {
      double v = scanner.nextInt();
      pq.add(v);
    }

    while (pq.size() > 1) {
      double a = pq.poll();
      double b = pq.poll();
      pq.add((a + b) * 0.5d);
    }

    System.out.println(pq.poll());
  } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int N = scanner.nextInt(); N scanner.nextInt() scanner.nextInt scanner PriorityQueue<Double> pq = new PriorityQueue<>(); pq new PriorityQueue<>() for (int i = 0; i < N; i++) {
      double v = scanner.nextInt();
      pq.add(v);
    } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
      double v = scanner.nextInt();
      pq.add(v);
    } {
      double v = scanner.nextInt();
      pq.add(v);
    } double v = scanner.nextInt(); v scanner.nextInt() scanner.nextInt scanner pq.add(v) pq.add pq v while (pq.size() > 1) {
      double a = pq.poll();
      double b = pq.poll();
      pq.add((a + b) * 0.5d);
    } pq.size() > 1 pq.size() pq.size pq 1 {
      double a = pq.poll();
      double b = pq.poll();
      pq.add((a + b) * 0.5d);
    } double a = pq.poll(); a pq.poll() pq.poll pq double b = pq.poll(); b pq.poll() pq.poll pq pq.add((a + b) * 0.5d) pq.add pq (a + b) * 0.5d (a + b) a b 0.5d System.out.println(pq.poll()) System.out.println System.out System System.out pq.poll() pq.poll pq String[] args args public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    int N = scanner.nextInt();
    PriorityQueue<Double> pq = new PriorityQueue<>();
    for (int i = 0; i < N; i++) {
      double v = scanner.nextInt();
      pq.add(v);
    }

    while (pq.size() > 1) {
      double a = pq.poll();
      double b = pq.poll();
      pq.add((a + b) * 0.5d);
    }

    System.out.println(pq.poll());
  }
} public class Main {
  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);

    int N = scanner.nextInt();
    PriorityQueue<Double> pq = new PriorityQueue<>();
    for (int i = 0; i < N; i++) {
      double v = scanner.nextInt();
      pq.add(v);
    }

    while (pq.size() > 1) {
      double a = pq.poll();
      double b = pq.poll();
      pq.add((a + b) * 0.5d);
    }

    System.out.println(pq.poll());
  }
} Main
import java.util.PriorityQueue;
import java.util.Scanner;

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

    int N = scanner.nextInt();
    PriorityQueue<Double> pq = new PriorityQueue<>();
    for (int i = 0; i < N; i++) {
      double v = scanner.nextInt();
      pq.add(v);
    }

    while (pq.size() > 1) {
      double a = pq.poll();
      double b = pq.poll();
      pq.add((a + b) * 0.5d);
    }

    System.out.println(pq.poll());
  }
}
