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