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

public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        int n = Integer.parseInt(in.nextLine());
        String[] params = in.nextLine().split(" ");

        double[] vs = new double[n];
        for( int i = 0 ; i < n ; i++ ){
            vs[i] = Double.parseDouble(params[i]);
        }

        Arrays.sort(vs);

        for( int i = 0 ; i < n - 1 ; i++ ){
            vs[i+1] = (vs[i] + vs[i+1])/2;
        }

        System.out.println( vs[n-1] );

    }

} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        int n = Integer.parseInt(in.nextLine());
        String[] params = in.nextLine().split(" ");

        double[] vs = new double[n];
        for( int i = 0 ; i < n ; i++ ){
            vs[i] = Double.parseDouble(params[i]);
        }

        Arrays.sort(vs);

        for( int i = 0 ; i < n - 1 ; i++ ){
            vs[i+1] = (vs[i] + vs[i+1])/2;
        }

        System.out.println( vs[n-1] );

    }

} Main public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        int n = Integer.parseInt(in.nextLine());
        String[] params = in.nextLine().split(" ");

        double[] vs = new double[n];
        for( int i = 0 ; i < n ; i++ ){
            vs[i] = Double.parseDouble(params[i]);
        }

        Arrays.sort(vs);

        for( int i = 0 ; i < n - 1 ; i++ ){
            vs[i+1] = (vs[i] + vs[i+1])/2;
        }

        System.out.println( vs[n-1] );

    } main {

        Scanner in = new Scanner(System.in);
        int n = Integer.parseInt(in.nextLine());
        String[] params = in.nextLine().split(" ");

        double[] vs = new double[n];
        for( int i = 0 ; i < n ; i++ ){
            vs[i] = Double.parseDouble(params[i]);
        }

        Arrays.sort(vs);

        for( int i = 0 ; i < n - 1 ; i++ ){
            vs[i+1] = (vs[i] + vs[i+1])/2;
        }

        System.out.println( vs[n-1] );

    } Scanner in = new Scanner(System.in); in new Scanner(System.in) int n = Integer.parseInt(in.nextLine()); n Integer.parseInt(in.nextLine()) Integer.parseInt Integer in.nextLine() in.nextLine in String[] params = in.nextLine().split(" "); params in.nextLine().split(" ") in.nextLine().split in.nextLine() in.nextLine in " " double[] vs = new double[n]; vs new double[n] n for( int i = 0 ; i < n ; i++ ){
            vs[i] = Double.parseDouble(params[i]);
        } int i = 0 ; int i = 0 ; i 0 i < n i n i++ i++ i {
            vs[i] = Double.parseDouble(params[i]);
        } {
            vs[i] = Double.parseDouble(params[i]);
        } vs[i] = Double.parseDouble(params[i]) vs[i] vs i Double.parseDouble(params[i]) Double.parseDouble Double params[i] params i Arrays.sort(vs) Arrays.sort Arrays vs for( int i = 0 ; i < n - 1 ; i++ ){
            vs[i+1] = (vs[i] + vs[i+1])/2;
        } int i = 0 ; int i = 0 ; i 0 i < n - 1 i n - 1 n 1 i++ i++ i {
            vs[i+1] = (vs[i] + vs[i+1])/2;
        } {
            vs[i+1] = (vs[i] + vs[i+1])/2;
        } vs[i+1] = (vs[i] + vs[i+1])/2 vs[i+1] vs i+1 i 1 (vs[i] + vs[i+1])/2 (vs[i] + vs[i+1]) vs[i] vs i vs[i+1] vs i+1 i 1 2 System.out.println( vs[n-1] ) System.out.println System.out System System.out vs[n-1] vs n-1 n 1 String[] args args public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        int n = Integer.parseInt(in.nextLine());
        String[] params = in.nextLine().split(" ");

        double[] vs = new double[n];
        for( int i = 0 ; i < n ; i++ ){
            vs[i] = Double.parseDouble(params[i]);
        }

        Arrays.sort(vs);

        for( int i = 0 ; i < n - 1 ; i++ ){
            vs[i+1] = (vs[i] + vs[i+1])/2;
        }

        System.out.println( vs[n-1] );

    }

} public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        int n = Integer.parseInt(in.nextLine());
        String[] params = in.nextLine().split(" ");

        double[] vs = new double[n];
        for( int i = 0 ; i < n ; i++ ){
            vs[i] = Double.parseDouble(params[i]);
        }

        Arrays.sort(vs);

        for( int i = 0 ; i < n - 1 ; i++ ){
            vs[i+1] = (vs[i] + vs[i+1])/2;
        }

        System.out.println( vs[n-1] );

    }

} Main
import java.util.Arrays;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner in = new Scanner(System.in);
        int n = Integer.parseInt(in.nextLine());
        String[] params = in.nextLine().split(" ");

        double[] vs = new double[n];
        for( int i = 0 ; i < n ; i++ ){
            vs[i] = Double.parseDouble(params[i]);
        }

        Arrays.sort(vs);

        for( int i = 0 ; i < n - 1 ; i++ ){
            vs[i+1] = (vs[i] + vs[i+1])/2;
        }

        System.out.println( vs[n-1] );

    }

}