import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        LinkedList<Double> v = new LinkedList<>();
        for (int i = 0; i < n; i++) {
            v.add(sc.nextDouble());
        }

        Collections.sort(v);

        while (v.size() >= 2) {
            double v1 = v.poll();
            double v2 = v.poll();
            v.offerFirst((v1 + v2) / 2);
        }

        System.out.print(v.get(0));
    }
} import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        LinkedList<Double> v = new LinkedList<>();
        for (int i = 0; i < n; i++) {
            v.add(sc.nextDouble());
        }

        Collections.sort(v);

        while (v.size() >= 2) {
            double v1 = v.poll();
            double v2 = v.poll();
            v.offerFirst((v1 + v2) / 2);
        }

        System.out.print(v.get(0));
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        LinkedList<Double> v = new LinkedList<>();
        for (int i = 0; i < n; i++) {
            v.add(sc.nextDouble());
        }

        Collections.sort(v);

        while (v.size() >= 2) {
            double v1 = v.poll();
            double v2 = v.poll();
            v.offerFirst((v1 + v2) / 2);
        }

        System.out.print(v.get(0));
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        LinkedList<Double> v = new LinkedList<>();
        for (int i = 0; i < n; i++) {
            v.add(sc.nextDouble());
        }

        Collections.sort(v);

        while (v.size() >= 2) {
            double v1 = v.poll();
            double v2 = v.poll();
            v.offerFirst((v1 + v2) / 2);
        }

        System.out.print(v.get(0));
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc LinkedList<Double> v = new LinkedList<>(); v new LinkedList<>() for (int i = 0; i < n; i++) {
            v.add(sc.nextDouble());
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            v.add(sc.nextDouble());
        } {
            v.add(sc.nextDouble());
        } v.add(sc.nextDouble()) v.add v sc.nextDouble() sc.nextDouble sc Collections.sort(v) Collections.sort Collections v while (v.size() >= 2) {
            double v1 = v.poll();
            double v2 = v.poll();
            v.offerFirst((v1 + v2) / 2);
        } v.size() >= 2 v.size() v.size v 2 {
            double v1 = v.poll();
            double v2 = v.poll();
            v.offerFirst((v1 + v2) / 2);
        } double v1 = v.poll(); v1 v.poll() v.poll v double v2 = v.poll(); v2 v.poll() v.poll v v.offerFirst((v1 + v2) / 2) v.offerFirst v (v1 + v2) / 2 (v1 + v2) v1 v2 2 System.out.print(v.get(0)) System.out.print System.out System System.out v.get(0) v.get v 0 String[] args args public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        LinkedList<Double> v = new LinkedList<>();
        for (int i = 0; i < n; i++) {
            v.add(sc.nextDouble());
        }

        Collections.sort(v);

        while (v.size() >= 2) {
            double v1 = v.poll();
            double v2 = v.poll();
            v.offerFirst((v1 + v2) / 2);
        }

        System.out.print(v.get(0));
    }
} public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        LinkedList<Double> v = new LinkedList<>();
        for (int i = 0; i < n; i++) {
            v.add(sc.nextDouble());
        }

        Collections.sort(v);

        while (v.size() >= 2) {
            double v1 = v.poll();
            double v2 = v.poll();
            v.offerFirst((v1 + v2) / 2);
        }

        System.out.print(v.get(0));
    }
} Main
import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();

        LinkedList<Double> v = new LinkedList<>();
        for (int i = 0; i < n; i++) {
            v.add(sc.nextDouble());
        }

        Collections.sort(v);

        while (v.size() >= 2) {
            double v1 = v.poll();
            double v2 = v.poll();
            v.offerFirst((v1 + v2) / 2);
        }

        System.out.print(v.get(0));
    }
}