import java.util.Scanner;
import java.util.HashMap;
import java.util.Map;
import java.util.Collections;
import java.util.List;
import java.util.Arrays;
import java.util.ArrayList;
import java.lang.Math;

public class Main {

    private static Scanner sc = new Scanner(System.in);
    private static int mod = (int) 10e8 + 7;

    public static void main(String[] args) {
        int n = sc.nextInt();
        double[] a = new double[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextDouble();
        }
        Arrays.sort(a);
        double sum = (a[0] + a[1]) / 2;
        for (int i = 2; i < n; i++) {
            sum = (sum + a[i]) / 2;
        }
        System.out.println(sum);
    }

} import java.util.Scanner; Scanner java.util import java.util.HashMap; HashMap java.util import java.util.Map; Map java.util import java.util.Collections; Collections java.util import java.util.List; List java.util import java.util.Arrays; Arrays java.util import java.util.ArrayList; ArrayList java.util import java.lang.Math; Math java.lang public class Main {

    private static Scanner sc = new Scanner(System.in);
    private static int mod = (int) 10e8 + 7;

    public static void main(String[] args) {
        int n = sc.nextInt();
        double[] a = new double[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextDouble();
        }
        Arrays.sort(a);
        double sum = (a[0] + a[1]) / 2;
        for (int i = 2; i < n; i++) {
            sum = (sum + a[i]) / 2;
        }
        System.out.println(sum);
    }

} Main private static Scanner sc = new Scanner(System.in); sc new Scanner(System.in) private static int mod = (int) 10e8 + 7; mod (int) 10e8 + 7 (int) 10e8 7 public static void main(String[] args) {
        int n = sc.nextInt();
        double[] a = new double[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextDouble();
        }
        Arrays.sort(a);
        double sum = (a[0] + a[1]) / 2;
        for (int i = 2; i < n; i++) {
            sum = (sum + a[i]) / 2;
        }
        System.out.println(sum);
    } main {
        int n = sc.nextInt();
        double[] a = new double[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextDouble();
        }
        Arrays.sort(a);
        double sum = (a[0] + a[1]) / 2;
        for (int i = 2; i < n; i++) {
            sum = (sum + a[i]) / 2;
        }
        System.out.println(sum);
    } int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc double[] a = new double[n]; a new double[n] n for (int i = 0; i < n; i++) {
            a[i] = sc.nextDouble();
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            a[i] = sc.nextDouble();
        } {
            a[i] = sc.nextDouble();
        } a[i] = sc.nextDouble() a[i] a i sc.nextDouble() sc.nextDouble sc Arrays.sort(a) Arrays.sort Arrays a double sum = (a[0] + a[1]) / 2; sum (a[0] + a[1]) / 2 (a[0] + a[1]) a[0] a 0 a[1] a 1 2 for (int i = 2; i < n; i++) {
            sum = (sum + a[i]) / 2;
        } int i = 2; int i = 2; i 2 i < n i n i++ i++ i {
            sum = (sum + a[i]) / 2;
        } {
            sum = (sum + a[i]) / 2;
        } sum = (sum + a[i]) / 2 sum (sum + a[i]) / 2 (sum + a[i]) sum a[i] a i 2 System.out.println(sum) System.out.println System.out System System.out sum String[] args args public class Main {

    private static Scanner sc = new Scanner(System.in);
    private static int mod = (int) 10e8 + 7;

    public static void main(String[] args) {
        int n = sc.nextInt();
        double[] a = new double[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextDouble();
        }
        Arrays.sort(a);
        double sum = (a[0] + a[1]) / 2;
        for (int i = 2; i < n; i++) {
            sum = (sum + a[i]) / 2;
        }
        System.out.println(sum);
    }

} public class Main {

    private static Scanner sc = new Scanner(System.in);
    private static int mod = (int) 10e8 + 7;

    public static void main(String[] args) {
        int n = sc.nextInt();
        double[] a = new double[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextDouble();
        }
        Arrays.sort(a);
        double sum = (a[0] + a[1]) / 2;
        for (int i = 2; i < n; i++) {
            sum = (sum + a[i]) / 2;
        }
        System.out.println(sum);
    }

} Main
import java.util.Scanner;
import java.util.HashMap;
import java.util.Map;
import java.util.Collections;
import java.util.List;
import java.util.Arrays;
import java.util.ArrayList;
import java.lang.Math;

public class Main {

    private static Scanner sc = new Scanner(System.in);
    private static int mod = (int) 10e8 + 7;

    public static void main(String[] args) {
        int n = sc.nextInt();
        double[] a = new double[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextDouble();
        }
        Arrays.sort(a);
        double sum = (a[0] + a[1]) / 2;
        for (int i = 2; i < n; i++) {
            sum = (sum + a[i]) / 2;
        }
        System.out.println(sum);
    }

}
