import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        float[] a = new float[n];
        for(int i =0; i< n; i++){
            a[i] = sc.nextFloat();
        }
        Arrays.sort(a);
        double ans = (a[0]+ a[1])/2;
        if(n>2) {
            for (int j = 2; j < n; j++) {
                ans = (ans + a[j]) / 2;

            }
        }
        System.out.println(ans);
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        float[] a = new float[n];
        for(int i =0; i< n; i++){
            a[i] = sc.nextFloat();
        }
        Arrays.sort(a);
        double ans = (a[0]+ a[1])/2;
        if(n>2) {
            for (int j = 2; j < n; j++) {
                ans = (ans + a[j]) / 2;

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

        int n = sc.nextInt();
        float[] a = new float[n];
        for(int i =0; i< n; i++){
            a[i] = sc.nextFloat();
        }
        Arrays.sort(a);
        double ans = (a[0]+ a[1])/2;
        if(n>2) {
            for (int j = 2; j < n; j++) {
                ans = (ans + a[j]) / 2;

            }
        }
        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        float[] a = new float[n];
        for(int i =0; i< n; i++){
            a[i] = sc.nextFloat();
        }
        Arrays.sort(a);
        double ans = (a[0]+ a[1])/2;
        if(n>2) {
            for (int j = 2; j < n; j++) {
                ans = (ans + a[j]) / 2;

            }
        }
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc float[] a = new float[n]; a new float[n] n for(int i =0; i< n; i++){
            a[i] = sc.nextFloat();
        } int i =0; int i =0; i 0 i< n i n i++ i++ i {
            a[i] = sc.nextFloat();
        } {
            a[i] = sc.nextFloat();
        } a[i] = sc.nextFloat() a[i] a i sc.nextFloat() sc.nextFloat sc Arrays.sort(a) Arrays.sort Arrays a double ans = (a[0]+ a[1])/2; ans (a[0]+ a[1])/2 (a[0]+ a[1]) a[0] a 0 a[1] a 1 2 if(n>2) {
            for (int j = 2; j < n; j++) {
                ans = (ans + a[j]) / 2;

            }
        } n>2 n 2 {
            for (int j = 2; j < n; j++) {
                ans = (ans + a[j]) / 2;

            }
        } for (int j = 2; j < n; j++) {
                ans = (ans + a[j]) / 2;

            } int j = 2; int j = 2; j 2 j < n j n j++ j++ j {
                ans = (ans + a[j]) / 2;

            } {
                ans = (ans + a[j]) / 2;

            } ans = (ans + a[j]) / 2 ans (ans + a[j]) / 2 (ans + a[j]) ans a[j] a j 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 sc = new Scanner(System.in);

        int n = sc.nextInt();
        float[] a = new float[n];
        for(int i =0; i< n; i++){
            a[i] = sc.nextFloat();
        }
        Arrays.sort(a);
        double ans = (a[0]+ a[1])/2;
        if(n>2) {
            for (int j = 2; j < n; j++) {
                ans = (ans + a[j]) / 2;

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

        int n = sc.nextInt();
        float[] a = new float[n];
        for(int i =0; i< n; i++){
            a[i] = sc.nextFloat();
        }
        Arrays.sort(a);
        double ans = (a[0]+ a[1])/2;
        if(n>2) {
            for (int j = 2; j < n; j++) {
                ans = (ans + a[j]) / 2;

            }
        }
        System.out.println(ans);
    }
} Main
import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        float[] a = new float[n];
        for(int i =0; i< n; i++){
            a[i] = sc.nextFloat();
        }
        Arrays.sort(a);
        double ans = (a[0]+ a[1])/2;
        if(n>2) {
            for (int j = 2; j < n; j++) {
                ans = (ans + a[j]) / 2;

            }
        }
        System.out.println(ans);
    }
}
