import java.util.*;
 
class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double[] v = new double[N];
     for(int i = 0; i < N; i++) {
        	v[i] = sc.nextDouble();
        }
      
        

        Arrays.sort(v);
      
      double sum1 = (v[0] + v[1])/2;
        
        if(N < 3) {
        	System.out.println(sum1);
        }else {
        	for(int i = 2; i < N; i++) {
            	sum1 = (sum1 + v[i])/2;
            }
            
            System.out.println(sum1);
        }
        
        sc.close();
    }
} import java.util.*; util.* java class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double[] v = new double[N];
     for(int i = 0; i < N; i++) {
        	v[i] = sc.nextDouble();
        }
      
        

        Arrays.sort(v);
      
      double sum1 = (v[0] + v[1])/2;
        
        if(N < 3) {
        	System.out.println(sum1);
        }else {
        	for(int i = 2; i < N; i++) {
            	sum1 = (sum1 + v[i])/2;
            }
            
            System.out.println(sum1);
        }
        
        sc.close();
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double[] v = new double[N];
     for(int i = 0; i < N; i++) {
        	v[i] = sc.nextDouble();
        }
      
        

        Arrays.sort(v);
      
      double sum1 = (v[0] + v[1])/2;
        
        if(N < 3) {
        	System.out.println(sum1);
        }else {
        	for(int i = 2; i < N; i++) {
            	sum1 = (sum1 + v[i])/2;
            }
            
            System.out.println(sum1);
        }
        
        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double[] v = new double[N];
     for(int i = 0; i < N; i++) {
        	v[i] = sc.nextDouble();
        }
      
        

        Arrays.sort(v);
      
      double sum1 = (v[0] + v[1])/2;
        
        if(N < 3) {
        	System.out.println(sum1);
        }else {
        	for(int i = 2; i < N; i++) {
            	sum1 = (sum1 + v[i])/2;
            }
            
            System.out.println(sum1);
        }
        
        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc double[] v = new double[N]; v new double[N] N for(int i = 0; i < N; i++) {
        	v[i] = sc.nextDouble();
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
        	v[i] = sc.nextDouble();
        } {
        	v[i] = sc.nextDouble();
        } v[i] = sc.nextDouble() v[i] v i sc.nextDouble() sc.nextDouble sc Arrays.sort(v) Arrays.sort Arrays v double sum1 = (v[0] + v[1])/2; sum1 (v[0] + v[1])/2 (v[0] + v[1]) v[0] v 0 v[1] v 1 2 if(N < 3) {
        	System.out.println(sum1);
        }else {
        	for(int i = 2; i < N; i++) {
            	sum1 = (sum1 + v[i])/2;
            }
            
            System.out.println(sum1);
        } N < 3 N 3 {
        	System.out.println(sum1);
        } System.out.println(sum1) System.out.println System.out System System.out sum1 {
        	for(int i = 2; i < N; i++) {
            	sum1 = (sum1 + v[i])/2;
            }
            
            System.out.println(sum1);
        } for(int i = 2; i < N; i++) {
            	sum1 = (sum1 + v[i])/2;
            } int i = 2; int i = 2; i 2 i < N i N i++ i++ i {
            	sum1 = (sum1 + v[i])/2;
            } {
            	sum1 = (sum1 + v[i])/2;
            } sum1 = (sum1 + v[i])/2 sum1 (sum1 + v[i])/2 (sum1 + v[i]) sum1 v[i] v i 2 System.out.println(sum1) System.out.println System.out System System.out sum1 sc.close() sc.close sc String[] args args
import java.util.*;
 
class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double[] v = new double[N];
     for(int i = 0; i < N; i++) {
        	v[i] = sc.nextDouble();
        }
      
        

        Arrays.sort(v);
      
      double sum1 = (v[0] + v[1])/2;
        
        if(N < 3) {
        	System.out.println(sum1);
        }else {
        	for(int i = 2; i < N; i++) {
            	sum1 = (sum1 + v[i])/2;
            }
            
            System.out.println(sum1);
        }
        
        sc.close();
    }
}
