import java.util.Scanner;
import java.util.ArrayList;
import java.util.Collections;
public class Main {

	public static void main(String[] args) {
       
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<Integer>();
        double ans = 0;
        for(int i = 0; i < a; i++){
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        ans = list.get(0);
        list.remove(0);
        while(list.size() > 0){
            ans = (ans + list.get(0)) / 2;
            list.remove(0);
        }
        System.out.println(ans);
    }
} import java.util.Scanner; Scanner java.util import java.util.ArrayList; ArrayList java.util import java.util.Collections; Collections java.util public class Main {

	public static void main(String[] args) {
       
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<Integer>();
        double ans = 0;
        for(int i = 0; i < a; i++){
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        ans = list.get(0);
        list.remove(0);
        while(list.size() > 0){
            ans = (ans + list.get(0)) / 2;
            list.remove(0);
        }
        System.out.println(ans);
    }
} Main public static void main(String[] args) {
       
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<Integer>();
        double ans = 0;
        for(int i = 0; i < a; i++){
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        ans = list.get(0);
        list.remove(0);
        while(list.size() > 0){
            ans = (ans + list.get(0)) / 2;
            list.remove(0);
        }
        System.out.println(ans);
    } main {
       
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<Integer>();
        double ans = 0;
        for(int i = 0; i < a; i++){
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        ans = list.get(0);
        list.remove(0);
        while(list.size() > 0){
            ans = (ans + list.get(0)) / 2;
            list.remove(0);
        }
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc ArrayList<Integer> list = new ArrayList<Integer>(); list new ArrayList<Integer>() double ans = 0; ans 0 for(int i = 0; i < a; i++){
            list.add(sc.nextInt());
        } int i = 0; int i = 0; i 0 i < a i a i++ i++ i {
            list.add(sc.nextInt());
        } {
            list.add(sc.nextInt());
        } list.add(sc.nextInt()) list.add list sc.nextInt() sc.nextInt sc Collections.sort(list) Collections.sort Collections list ans = list.get(0) ans list.get(0) list.get list 0 list.remove(0) list.remove list 0 while(list.size() > 0){
            ans = (ans + list.get(0)) / 2;
            list.remove(0);
        } list.size() > 0 list.size() list.size list 0 {
            ans = (ans + list.get(0)) / 2;
            list.remove(0);
        } ans = (ans + list.get(0)) / 2 ans (ans + list.get(0)) / 2 (ans + list.get(0)) ans list.get(0) list.get list 0 2 list.remove(0) list.remove list 0 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 a = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<Integer>();
        double ans = 0;
        for(int i = 0; i < a; i++){
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        ans = list.get(0);
        list.remove(0);
        while(list.size() > 0){
            ans = (ans + list.get(0)) / 2;
            list.remove(0);
        }
        System.out.println(ans);
    }
} public class Main {

	public static void main(String[] args) {
       
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<Integer>();
        double ans = 0;
        for(int i = 0; i < a; i++){
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        ans = list.get(0);
        list.remove(0);
        while(list.size() > 0){
            ans = (ans + list.get(0)) / 2;
            list.remove(0);
        }
        System.out.println(ans);
    }
} Main
import java.util.Scanner;
import java.util.ArrayList;
import java.util.Collections;
public class Main {

	public static void main(String[] args) {
       
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        ArrayList<Integer> list = new ArrayList<Integer>();
        double ans = 0;
        for(int i = 0; i < a; i++){
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        ans = list.get(0);
        list.remove(0);
        while(list.size() > 0){
            ans = (ans + list.get(0)) / 2;
            list.remove(0);
        }
        System.out.println(ans);
    }
}