import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan=new Scanner(System.in);
        int n=scan.nextInt();
        int A[]=new int[n];
//        double B[]=new double[n];

        for(int i=0;i<n;i++){
            A[i]=scan.nextInt();
        }

        double c=0;
        Arrays.sort(A);
        c=(A[0]+A[1])/2.0;
        for(int i=2;i<n;i++){
            c=(c+A[i])/2.0;
        }
        System.out.println(c);
    }
} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner scan=new Scanner(System.in);
        int n=scan.nextInt();
        int A[]=new int[n];
//        double B[]=new double[n];

        for(int i=0;i<n;i++){
            A[i]=scan.nextInt();
        }

        double c=0;
        Arrays.sort(A);
        c=(A[0]+A[1])/2.0;
        for(int i=2;i<n;i++){
            c=(c+A[i])/2.0;
        }
        System.out.println(c);
    }
} Main public static void main(String[] args) {
        Scanner scan=new Scanner(System.in);
        int n=scan.nextInt();
        int A[]=new int[n];
//        double B[]=new double[n];

        for(int i=0;i<n;i++){
            A[i]=scan.nextInt();
        }

        double c=0;
        Arrays.sort(A);
        c=(A[0]+A[1])/2.0;
        for(int i=2;i<n;i++){
            c=(c+A[i])/2.0;
        }
        System.out.println(c);
    } main {
        Scanner scan=new Scanner(System.in);
        int n=scan.nextInt();
        int A[]=new int[n];
//        double B[]=new double[n];

        for(int i=0;i<n;i++){
            A[i]=scan.nextInt();
        }

        double c=0;
        Arrays.sort(A);
        c=(A[0]+A[1])/2.0;
        for(int i=2;i<n;i++){
            c=(c+A[i])/2.0;
        }
        System.out.println(c);
    } Scanner scan=new Scanner(System.in); scan new Scanner(System.in) int n=scan.nextInt(); n scan.nextInt() scan.nextInt scan int A[]=new int[n]; A new int[n] n for(int i=0;i<n;i++){
            A[i]=scan.nextInt();
        } int i=0; int i=0; i 0 i<n i n i++ i++ i {
            A[i]=scan.nextInt();
        } {
            A[i]=scan.nextInt();
        } A[i]=scan.nextInt() A[i] A i scan.nextInt() scan.nextInt scan double c=0; c 0 Arrays.sort(A) Arrays.sort Arrays A c=(A[0]+A[1])/2.0 c (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++){
            c=(c+A[i])/2.0;
        } int i=2; int i=2; i 2 i<n i n i++ i++ i {
            c=(c+A[i])/2.0;
        } {
            c=(c+A[i])/2.0;
        } c=(c+A[i])/2.0 c (c+A[i])/2.0 (c+A[i]) c A[i] A i 2.0 System.out.println(c) System.out.println System.out System System.out c String[] args args public class Main {
    public static void main(String[] args) {
        Scanner scan=new Scanner(System.in);
        int n=scan.nextInt();
        int A[]=new int[n];
//        double B[]=new double[n];

        for(int i=0;i<n;i++){
            A[i]=scan.nextInt();
        }

        double c=0;
        Arrays.sort(A);
        c=(A[0]+A[1])/2.0;
        for(int i=2;i<n;i++){
            c=(c+A[i])/2.0;
        }
        System.out.println(c);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner scan=new Scanner(System.in);
        int n=scan.nextInt();
        int A[]=new int[n];
//        double B[]=new double[n];

        for(int i=0;i<n;i++){
            A[i]=scan.nextInt();
        }

        double c=0;
        Arrays.sort(A);
        c=(A[0]+A[1])/2.0;
        for(int i=2;i<n;i++){
            c=(c+A[i])/2.0;
        }
        System.out.println(c);
    }
} Main
import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan=new Scanner(System.in);
        int n=scan.nextInt();
        int A[]=new int[n];
//        double B[]=new double[n];

        for(int i=0;i<n;i++){
            A[i]=scan.nextInt();
        }

        double c=0;
        Arrays.sort(A);
        c=(A[0]+A[1])/2.0;
        for(int i=2;i<n;i++){
            c=(c+A[i])/2.0;
        }
        System.out.println(c);
    }
}
