import java.util.*;
import java.io.*;
public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        OutputStream pr = System.out;
        PrintWriter out = new PrintWriter(pr);
        int n = sc.nextInt();
        double[] array = new double[n];
        for(int i=0;i<n;i++){
            array[i]=sc.nextDouble();
        }
        double d=0.0;
        if(n==1){
            d = array[0];
        }else if(n==2){
            d = (array[0]+array[1])/2;
        }else{
            Arrays.sort(array);
            d = (array[0]+array[1])/2;
            for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            }
        }
        out.print(d);
        out.close();
    }
    public static long gcd(long a,long b){
        if(a==0){
            return b;
        }else{
            return gcd(b%a,a);
        }
    }
} import java.util.*; util.* java import java.io.*; io.* java public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        OutputStream pr = System.out;
        PrintWriter out = new PrintWriter(pr);
        int n = sc.nextInt();
        double[] array = new double[n];
        for(int i=0;i<n;i++){
            array[i]=sc.nextDouble();
        }
        double d=0.0;
        if(n==1){
            d = array[0];
        }else if(n==2){
            d = (array[0]+array[1])/2;
        }else{
            Arrays.sort(array);
            d = (array[0]+array[1])/2;
            for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            }
        }
        out.print(d);
        out.close();
    }
    public static long gcd(long a,long b){
        if(a==0){
            return b;
        }else{
            return gcd(b%a,a);
        }
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        OutputStream pr = System.out;
        PrintWriter out = new PrintWriter(pr);
        int n = sc.nextInt();
        double[] array = new double[n];
        for(int i=0;i<n;i++){
            array[i]=sc.nextDouble();
        }
        double d=0.0;
        if(n==1){
            d = array[0];
        }else if(n==2){
            d = (array[0]+array[1])/2;
        }else{
            Arrays.sort(array);
            d = (array[0]+array[1])/2;
            for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            }
        }
        out.print(d);
        out.close();
    } main {
        Scanner sc = new Scanner(System.in);
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        OutputStream pr = System.out;
        PrintWriter out = new PrintWriter(pr);
        int n = sc.nextInt();
        double[] array = new double[n];
        for(int i=0;i<n;i++){
            array[i]=sc.nextDouble();
        }
        double d=0.0;
        if(n==1){
            d = array[0];
        }else if(n==2){
            d = (array[0]+array[1])/2;
        }else{
            Arrays.sort(array);
            d = (array[0]+array[1])/2;
            for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            }
        }
        out.print(d);
        out.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) OutputStream pr = System.out; pr System.out System System.out PrintWriter out = new PrintWriter(pr); out new PrintWriter(pr) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc double[] array = new double[n]; array new double[n] n for(int i=0;i<n;i++){
            array[i]=sc.nextDouble();
        } int i=0; int i=0; i 0 i<n i n i++ i++ i {
            array[i]=sc.nextDouble();
        } {
            array[i]=sc.nextDouble();
        } array[i]=sc.nextDouble() array[i] array i sc.nextDouble() sc.nextDouble sc double d=0.0; d 0.0 if(n==1){
            d = array[0];
        }else if(n==2){
            d = (array[0]+array[1])/2;
        }else{
            Arrays.sort(array);
            d = (array[0]+array[1])/2;
            for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            }
        } n==1 n 1 {
            d = array[0];
        } d = array[0] d array[0] array 0 if(n==2){
            d = (array[0]+array[1])/2;
        }else{
            Arrays.sort(array);
            d = (array[0]+array[1])/2;
            for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            }
        } n==2 n 2 {
            d = (array[0]+array[1])/2;
        } d = (array[0]+array[1])/2 d (array[0]+array[1])/2 (array[0]+array[1]) array[0] array 0 array[1] array 1 2 {
            Arrays.sort(array);
            d = (array[0]+array[1])/2;
            for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            }
        } Arrays.sort(array) Arrays.sort Arrays array d = (array[0]+array[1])/2 d (array[0]+array[1])/2 (array[0]+array[1]) array[0] array 0 array[1] array 1 2 for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            } int i=2; int i=2; i 2 i<n i n i++ i++ i {
                d=(d+array[i])/2;
            } {
                d=(d+array[i])/2;
            } d=(d+array[i])/2 d (d+array[i])/2 (d+array[i]) d array[i] array i 2 out.print(d) out.print out d out.close() out.close out String[] args args public static long gcd(long a,long b){
        if(a==0){
            return b;
        }else{
            return gcd(b%a,a);
        }
    } gcd {
        if(a==0){
            return b;
        }else{
            return gcd(b%a,a);
        }
    } if(a==0){
            return b;
        }else{
            return gcd(b%a,a);
        } a==0 a 0 {
            return b;
        } return b; b {
            return gcd(b%a,a);
        } return gcd(b%a,a); gcd(b%a,a) gcd b%a b a a long a a long b b public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        OutputStream pr = System.out;
        PrintWriter out = new PrintWriter(pr);
        int n = sc.nextInt();
        double[] array = new double[n];
        for(int i=0;i<n;i++){
            array[i]=sc.nextDouble();
        }
        double d=0.0;
        if(n==1){
            d = array[0];
        }else if(n==2){
            d = (array[0]+array[1])/2;
        }else{
            Arrays.sort(array);
            d = (array[0]+array[1])/2;
            for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            }
        }
        out.print(d);
        out.close();
    }
    public static long gcd(long a,long b){
        if(a==0){
            return b;
        }else{
            return gcd(b%a,a);
        }
    }
} public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        OutputStream pr = System.out;
        PrintWriter out = new PrintWriter(pr);
        int n = sc.nextInt();
        double[] array = new double[n];
        for(int i=0;i<n;i++){
            array[i]=sc.nextDouble();
        }
        double d=0.0;
        if(n==1){
            d = array[0];
        }else if(n==2){
            d = (array[0]+array[1])/2;
        }else{
            Arrays.sort(array);
            d = (array[0]+array[1])/2;
            for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            }
        }
        out.print(d);
        out.close();
    }
    public static long gcd(long a,long b){
        if(a==0){
            return b;
        }else{
            return gcd(b%a,a);
        }
    }
} Main
import java.util.*;
import java.io.*;
public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        OutputStream pr = System.out;
        PrintWriter out = new PrintWriter(pr);
        int n = sc.nextInt();
        double[] array = new double[n];
        for(int i=0;i<n;i++){
            array[i]=sc.nextDouble();
        }
        double d=0.0;
        if(n==1){
            d = array[0];
        }else if(n==2){
            d = (array[0]+array[1])/2;
        }else{
            Arrays.sort(array);
            d = (array[0]+array[1])/2;
            for(int i=2;i<n;i++){
                d=(d+array[i])/2;
            }
        }
        out.print(d);
        out.close();
    }
    public static long gcd(long a,long b){
        if(a==0){
            return b;
        }else{
            return gcd(b%a,a);
        }
    }
}