import java.util.*;

public class Main{
	public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
      	int n = scan.nextInt();
      	double[] v = new double[n];
      	for (int i = 0; i < n; i ++){
         	v[i] = scan.nextDouble(); 
        }
      	Arrays.sort(v);
      	for(int j = 0; j < n-1; j++){
        	v[j + 1] = (v[j] + v[j + 1]) / 2;
        }
      	System.out.print(v[n-1]);
    }
} import java.util.*; util.* java public class Main{
	public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
      	int n = scan.nextInt();
      	double[] v = new double[n];
      	for (int i = 0; i < n; i ++){
         	v[i] = scan.nextDouble(); 
        }
      	Arrays.sort(v);
      	for(int j = 0; j < n-1; j++){
        	v[j + 1] = (v[j] + v[j + 1]) / 2;
        }
      	System.out.print(v[n-1]);
    }
} Main public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
      	int n = scan.nextInt();
      	double[] v = new double[n];
      	for (int i = 0; i < n; i ++){
         	v[i] = scan.nextDouble(); 
        }
      	Arrays.sort(v);
      	for(int j = 0; j < n-1; j++){
        	v[j + 1] = (v[j] + v[j + 1]) / 2;
        }
      	System.out.print(v[n-1]);
    } main {
    	Scanner scan = new Scanner(System.in);
      	int n = scan.nextInt();
      	double[] v = new double[n];
      	for (int i = 0; i < n; i ++){
         	v[i] = scan.nextDouble(); 
        }
      	Arrays.sort(v);
      	for(int j = 0; j < n-1; j++){
        	v[j + 1] = (v[j] + v[j + 1]) / 2;
        }
      	System.out.print(v[n-1]);
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int n = scan.nextInt(); n scan.nextInt() scan.nextInt scan double[] v = new double[n]; v new double[n] n for (int i = 0; i < n; i ++){
         	v[i] = scan.nextDouble(); 
        } int i = 0; int i = 0; i 0 i < n i n i ++ i ++ i {
         	v[i] = scan.nextDouble(); 
        } {
         	v[i] = scan.nextDouble(); 
        } v[i] = scan.nextDouble() v[i] v i scan.nextDouble() scan.nextDouble scan Arrays.sort(v) Arrays.sort Arrays v for(int j = 0; j < n-1; j++){
        	v[j + 1] = (v[j] + v[j + 1]) / 2;
        } int j = 0; int j = 0; j 0 j < n-1 j n-1 n 1 j++ j++ j {
        	v[j + 1] = (v[j] + v[j + 1]) / 2;
        } {
        	v[j + 1] = (v[j] + v[j + 1]) / 2;
        } v[j + 1] = (v[j] + v[j + 1]) / 2 v[j + 1] v j + 1 j 1 (v[j] + v[j + 1]) / 2 (v[j] + v[j + 1]) v[j] v j v[j + 1] v j + 1 j 1 2 System.out.print(v[n-1]) System.out.print System.out System System.out v[n-1] v n-1 n 1 String[] args args public class Main{
	public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
      	int n = scan.nextInt();
      	double[] v = new double[n];
      	for (int i = 0; i < n; i ++){
         	v[i] = scan.nextDouble(); 
        }
      	Arrays.sort(v);
      	for(int j = 0; j < n-1; j++){
        	v[j + 1] = (v[j] + v[j + 1]) / 2;
        }
      	System.out.print(v[n-1]);
    }
} public class Main{
	public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
      	int n = scan.nextInt();
      	double[] v = new double[n];
      	for (int i = 0; i < n; i ++){
         	v[i] = scan.nextDouble(); 
        }
      	Arrays.sort(v);
      	for(int j = 0; j < n-1; j++){
        	v[j + 1] = (v[j] + v[j + 1]) / 2;
        }
      	System.out.print(v[n-1]);
    }
} Main
import java.util.*;

public class Main{
	public static void main(String[] args){
    	Scanner scan = new Scanner(System.in);
      	int n = scan.nextInt();
      	double[] v = new double[n];
      	for (int i = 0; i < n; i ++){
         	v[i] = scan.nextDouble(); 
        }
      	Arrays.sort(v);
      	for(int j = 0; j < n-1; j++){
        	v[j + 1] = (v[j] + v[j + 1]) / 2;
        }
      	System.out.print(v[n-1]);
    }
}