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

public class Main {


    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        main3(sc);
    }

    public static void main3(Scanner sc) {

    	int N = sc.nextInt();
        float[] all = new float[N];

        for (int i = 0; i < N; i++) {
        	all[i] = sc.nextFloat();
        }

        Arrays.sort(all);

        float value = (all[0] + all[1])/2;

        for (int i = 2; i < N; i++) {
        	value = (value + all[i])/2;
        }

        System.out.println(value);
    }

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


    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        main3(sc);
    }

    public static void main3(Scanner sc) {

    	int N = sc.nextInt();
        float[] all = new float[N];

        for (int i = 0; i < N; i++) {
        	all[i] = sc.nextFloat();
        }

        Arrays.sort(all);

        float value = (all[0] + all[1])/2;

        for (int i = 2; i < N; i++) {
        	value = (value + all[i])/2;
        }

        System.out.println(value);
    }

} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        main3(sc);
    } main {
        Scanner sc = new Scanner(System.in);
        main3(sc);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) main3(sc) main3 sc String[] args args public static void main3(Scanner sc) {

    	int N = sc.nextInt();
        float[] all = new float[N];

        for (int i = 0; i < N; i++) {
        	all[i] = sc.nextFloat();
        }

        Arrays.sort(all);

        float value = (all[0] + all[1])/2;

        for (int i = 2; i < N; i++) {
        	value = (value + all[i])/2;
        }

        System.out.println(value);
    } main3 {

    	int N = sc.nextInt();
        float[] all = new float[N];

        for (int i = 0; i < N; i++) {
        	all[i] = sc.nextFloat();
        }

        Arrays.sort(all);

        float value = (all[0] + all[1])/2;

        for (int i = 2; i < N; i++) {
        	value = (value + all[i])/2;
        }

        System.out.println(value);
    } int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc float[] all = new float[N]; all new float[N] N for (int i = 0; i < N; i++) {
        	all[i] = sc.nextFloat();
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
        	all[i] = sc.nextFloat();
        } {
        	all[i] = sc.nextFloat();
        } all[i] = sc.nextFloat() all[i] all i sc.nextFloat() sc.nextFloat sc Arrays.sort(all) Arrays.sort Arrays all float value = (all[0] + all[1])/2; value (all[0] + all[1])/2 (all[0] + all[1]) all[0] all 0 all[1] all 1 2 for (int i = 2; i < N; i++) {
        	value = (value + all[i])/2;
        } int i = 2; int i = 2; i 2 i < N i N i++ i++ i {
        	value = (value + all[i])/2;
        } {
        	value = (value + all[i])/2;
        } value = (value + all[i])/2 value (value + all[i])/2 (value + all[i]) value all[i] all i 2 System.out.println(value) System.out.println System.out System System.out value Scanner sc sc public class Main {


    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        main3(sc);
    }

    public static void main3(Scanner sc) {

    	int N = sc.nextInt();
        float[] all = new float[N];

        for (int i = 0; i < N; i++) {
        	all[i] = sc.nextFloat();
        }

        Arrays.sort(all);

        float value = (all[0] + all[1])/2;

        for (int i = 2; i < N; i++) {
        	value = (value + all[i])/2;
        }

        System.out.println(value);
    }

} public class Main {


    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        main3(sc);
    }

    public static void main3(Scanner sc) {

    	int N = sc.nextInt();
        float[] all = new float[N];

        for (int i = 0; i < N; i++) {
        	all[i] = sc.nextFloat();
        }

        Arrays.sort(all);

        float value = (all[0] + all[1])/2;

        for (int i = 2; i < N; i++) {
        	value = (value + all[i])/2;
        }

        System.out.println(value);
    }

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

public class Main {


    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        main3(sc);
    }

    public static void main3(Scanner sc) {

    	int N = sc.nextInt();
        float[] all = new float[N];

        for (int i = 0; i < N; i++) {
        	all[i] = sc.nextFloat();
        }

        Arrays.sort(all);

        float value = (all[0] + all[1])/2;

        for (int i = 2; i < N; i++) {
        	value = (value + all[i])/2;
        }

        System.out.println(value);
    }

}