import java.util.*;

class Main {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int a[] = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
        }
        Arrays.sort(a);
        double x = (a[0] + a[1]) / 2.0;
        for (int i = 2; i < n; i++) {
            x = (x + a[i]) / 2;
        }
        System.out.printf("%f\n", x);
    }
} import java.util.*; util.* java class Main {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int a[] = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
        }
        Arrays.sort(a);
        double x = (a[0] + a[1]) / 2.0;
        for (int i = 2; i < n; i++) {
            x = (x + a[i]) / 2;
        }
        System.out.printf("%f\n", x);
    }
} Main public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int a[] = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
        }
        Arrays.sort(a);
        double x = (a[0] + a[1]) / 2.0;
        for (int i = 2; i < n; i++) {
            x = (x + a[i]) / 2;
        }
        System.out.printf("%f\n", x);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int a[] = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
        }
        Arrays.sort(a);
        double x = (a[0] + a[1]) / 2.0;
        for (int i = 2; i < n; i++) {
            x = (x + a[i]) / 2;
        }
        System.out.printf("%f\n", x);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int a[] = new int[n]; a new int[n] n for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            a[i] = sc.nextInt();
        } {
            a[i] = sc.nextInt();
        } a[i] = sc.nextInt() a[i] a i sc.nextInt() sc.nextInt sc Arrays.sort(a) Arrays.sort Arrays a double x = (a[0] + a[1]) / 2.0; x (a[0] + a[1]) / 2.0 (a[0] + a[1]) a[0] a 0 a[1] a 1 2.0 for (int i = 2; i < n; i++) {
            x = (x + a[i]) / 2;
        } int i = 2; int i = 2; i 2 i < n i n i++ i++ i {
            x = (x + a[i]) / 2;
        } {
            x = (x + a[i]) / 2;
        } x = (x + a[i]) / 2 x (x + a[i]) / 2 (x + a[i]) x a[i] a i 2 System.out.printf("%f\n", x) System.out.printf System.out System System.out "%f\n" x String args[] args
import java.util.*;

class Main {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int a[] = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
        }
        Arrays.sort(a);
        double x = (a[0] + a[1]) / 2.0;
        for (int i = 2; i < n; i++) {
            x = (x + a[i]) / 2;
        }
        System.out.printf("%f\n", x);
    }
}
