import java.io.BufferedReader;
import java.io.*;
import java.util.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Collections;
import java.util.Arrays;

public class Main {
	public static void main(final String[] args){
    
    Scanner sc = new Scanner(System.in);
    List<Double> list = new ArrayList<>();
    int n = sc.nextInt();
    double sum = 0;
    double maker = 0;

    for(int i = 0 ; i < n ; i++){
        list.add(sc.nextDouble());
    }

    Collections.sort(list);
    maker = (list.get(0) + list.get(1) ) / 2;

    if(list.size() <= 2){
        System.out.println(maker);
    }else{
        for(int i = 2 ; i < n; i++){
            maker = (maker + list.get(i)) / 2;
        }
        System.out.println(maker);
    }
    






    
    
    







}
} import java.io.BufferedReader; BufferedReader java.io import java.io.*; io.* java import java.util.*; util.* java import java.util.ArrayList; ArrayList java.util import java.util.Iterator; Iterator java.util import java.util.List; List java.util import java.util.Collections; Collections java.util import java.util.Arrays; Arrays java.util public class Main {
	public static void main(final String[] args){
    
    Scanner sc = new Scanner(System.in);
    List<Double> list = new ArrayList<>();
    int n = sc.nextInt();
    double sum = 0;
    double maker = 0;

    for(int i = 0 ; i < n ; i++){
        list.add(sc.nextDouble());
    }

    Collections.sort(list);
    maker = (list.get(0) + list.get(1) ) / 2;

    if(list.size() <= 2){
        System.out.println(maker);
    }else{
        for(int i = 2 ; i < n; i++){
            maker = (maker + list.get(i)) / 2;
        }
        System.out.println(maker);
    }
    






    
    
    







}
} Main public static void main(final String[] args){
    
    Scanner sc = new Scanner(System.in);
    List<Double> list = new ArrayList<>();
    int n = sc.nextInt();
    double sum = 0;
    double maker = 0;

    for(int i = 0 ; i < n ; i++){
        list.add(sc.nextDouble());
    }

    Collections.sort(list);
    maker = (list.get(0) + list.get(1) ) / 2;

    if(list.size() <= 2){
        System.out.println(maker);
    }else{
        for(int i = 2 ; i < n; i++){
            maker = (maker + list.get(i)) / 2;
        }
        System.out.println(maker);
    }
    






    
    
    







} main {
    
    Scanner sc = new Scanner(System.in);
    List<Double> list = new ArrayList<>();
    int n = sc.nextInt();
    double sum = 0;
    double maker = 0;

    for(int i = 0 ; i < n ; i++){
        list.add(sc.nextDouble());
    }

    Collections.sort(list);
    maker = (list.get(0) + list.get(1) ) / 2;

    if(list.size() <= 2){
        System.out.println(maker);
    }else{
        for(int i = 2 ; i < n; i++){
            maker = (maker + list.get(i)) / 2;
        }
        System.out.println(maker);
    }
    






    
    
    







} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) List<Double> list = new ArrayList<>(); list new ArrayList<>() int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc double sum = 0; sum 0 double maker = 0; maker 0 for(int i = 0 ; i < n ; i++){
        list.add(sc.nextDouble());
    } int i = 0 ; int i = 0 ; i 0 i < n i n i++ i++ i {
        list.add(sc.nextDouble());
    } {
        list.add(sc.nextDouble());
    } list.add(sc.nextDouble()) list.add list sc.nextDouble() sc.nextDouble sc Collections.sort(list) Collections.sort Collections list maker = (list.get(0) + list.get(1) ) / 2 maker (list.get(0) + list.get(1) ) / 2 (list.get(0) + list.get(1) ) list.get(0) list.get list 0 list.get(1) list.get list 1 2 if(list.size() <= 2){
        System.out.println(maker);
    }else{
        for(int i = 2 ; i < n; i++){
            maker = (maker + list.get(i)) / 2;
        }
        System.out.println(maker);
    } list.size() <= 2 list.size() list.size list 2 {
        System.out.println(maker);
    } System.out.println(maker) System.out.println System.out System System.out maker {
        for(int i = 2 ; i < n; i++){
            maker = (maker + list.get(i)) / 2;
        }
        System.out.println(maker);
    } for(int i = 2 ; i < n; i++){
            maker = (maker + list.get(i)) / 2;
        } int i = 2 ; int i = 2 ; i 2 i < n i n i++ i++ i {
            maker = (maker + list.get(i)) / 2;
        } {
            maker = (maker + list.get(i)) / 2;
        } maker = (maker + list.get(i)) / 2 maker (maker + list.get(i)) / 2 (maker + list.get(i)) maker list.get(i) list.get list i 2 System.out.println(maker) System.out.println System.out System System.out maker final String[] args args public class Main {
	public static void main(final String[] args){
    
    Scanner sc = new Scanner(System.in);
    List<Double> list = new ArrayList<>();
    int n = sc.nextInt();
    double sum = 0;
    double maker = 0;

    for(int i = 0 ; i < n ; i++){
        list.add(sc.nextDouble());
    }

    Collections.sort(list);
    maker = (list.get(0) + list.get(1) ) / 2;

    if(list.size() <= 2){
        System.out.println(maker);
    }else{
        for(int i = 2 ; i < n; i++){
            maker = (maker + list.get(i)) / 2;
        }
        System.out.println(maker);
    }
    






    
    
    







}
} public class Main {
	public static void main(final String[] args){
    
    Scanner sc = new Scanner(System.in);
    List<Double> list = new ArrayList<>();
    int n = sc.nextInt();
    double sum = 0;
    double maker = 0;

    for(int i = 0 ; i < n ; i++){
        list.add(sc.nextDouble());
    }

    Collections.sort(list);
    maker = (list.get(0) + list.get(1) ) / 2;

    if(list.size() <= 2){
        System.out.println(maker);
    }else{
        for(int i = 2 ; i < n; i++){
            maker = (maker + list.get(i)) / 2;
        }
        System.out.println(maker);
    }
    






    
    
    







}
} Main
import java.io.BufferedReader;
import java.io.*;
import java.util.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Collections;
import java.util.Arrays;

public class Main {
	public static void main(final String[] args){
    
    Scanner sc = new Scanner(System.in);
    List<Double> list = new ArrayList<>();
    int n = sc.nextInt();
    double sum = 0;
    double maker = 0;

    for(int i = 0 ; i < n ; i++){
        list.add(sc.nextDouble());
    }

    Collections.sort(list);
    maker = (list.get(0) + list.get(1) ) / 2;

    if(list.size() <= 2){
        System.out.println(maker);
    }else{
        for(int i = 2 ; i < n; i++){
            maker = (maker + list.get(i)) / 2;
        }
        System.out.println(maker);
    }
    






    
    
    







}
}