import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        ArrayList<Integer> v = new ArrayList<>();
        for (int i=0;i<n;i++){
            v.add(scanner.nextInt());
        }
        Collections.sort(v);
        double ans = (((double)v.get(0)) + ((double)v.get(1)))/2;
        for (int i=2;i<n;i++){
            ans = (ans + ((double)v.get(i)))/2;
        }
        System.out.println(ans);

    }

} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        ArrayList<Integer> v = new ArrayList<>();
        for (int i=0;i<n;i++){
            v.add(scanner.nextInt());
        }
        Collections.sort(v);
        double ans = (((double)v.get(0)) + ((double)v.get(1)))/2;
        for (int i=2;i<n;i++){
            ans = (ans + ((double)v.get(i)))/2;
        }
        System.out.println(ans);

    }

} Main public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        ArrayList<Integer> v = new ArrayList<>();
        for (int i=0;i<n;i++){
            v.add(scanner.nextInt());
        }
        Collections.sort(v);
        double ans = (((double)v.get(0)) + ((double)v.get(1)))/2;
        for (int i=2;i<n;i++){
            ans = (ans + ((double)v.get(i)))/2;
        }
        System.out.println(ans);

    } main {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        ArrayList<Integer> v = new ArrayList<>();
        for (int i=0;i<n;i++){
            v.add(scanner.nextInt());
        }
        Collections.sort(v);
        double ans = (((double)v.get(0)) + ((double)v.get(1)))/2;
        for (int i=2;i<n;i++){
            ans = (ans + ((double)v.get(i)))/2;
        }
        System.out.println(ans);

    } Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int n = scanner.nextInt(); n scanner.nextInt() scanner.nextInt scanner ArrayList<Integer> v = new ArrayList<>(); v new ArrayList<>() for (int i=0;i<n;i++){
            v.add(scanner.nextInt());
        } int i=0; int i=0; i 0 i<n i n i++ i++ i {
            v.add(scanner.nextInt());
        } {
            v.add(scanner.nextInt());
        } v.add(scanner.nextInt()) v.add v scanner.nextInt() scanner.nextInt scanner Collections.sort(v) Collections.sort Collections v double ans = (((double)v.get(0)) + ((double)v.get(1)))/2; ans (((double)v.get(0)) + ((double)v.get(1)))/2 (((double)v.get(0)) + ((double)v.get(1))) ((double)v.get(0)) v.get v 0 ((double)v.get(1)) v.get v 1 2 for (int i=2;i<n;i++){
            ans = (ans + ((double)v.get(i)))/2;
        } int i=2; int i=2; i 2 i<n i n i++ i++ i {
            ans = (ans + ((double)v.get(i)))/2;
        } {
            ans = (ans + ((double)v.get(i)))/2;
        } ans = (ans + ((double)v.get(i)))/2 ans (ans + ((double)v.get(i)))/2 (ans + ((double)v.get(i))) ans ((double)v.get(i)) v.get v i 2 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        ArrayList<Integer> v = new ArrayList<>();
        for (int i=0;i<n;i++){
            v.add(scanner.nextInt());
        }
        Collections.sort(v);
        double ans = (((double)v.get(0)) + ((double)v.get(1)))/2;
        for (int i=2;i<n;i++){
            ans = (ans + ((double)v.get(i)))/2;
        }
        System.out.println(ans);

    }

} public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        ArrayList<Integer> v = new ArrayList<>();
        for (int i=0;i<n;i++){
            v.add(scanner.nextInt());
        }
        Collections.sort(v);
        double ans = (((double)v.get(0)) + ((double)v.get(1)))/2;
        for (int i=2;i<n;i++){
            ans = (ans + ((double)v.get(i)))/2;
        }
        System.out.println(ans);

    }

} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        ArrayList<Integer> v = new ArrayList<>();
        for (int i=0;i<n;i++){
            v.add(scanner.nextInt());
        }
        Collections.sort(v);
        double ans = (((double)v.get(0)) + ((double)v.get(1)))/2;
        for (int i=2;i<n;i++){
            ans = (ans + ((double)v.get(i)))/2;
        }
        System.out.println(ans);

    }

}
