import java.util.*;
import java.io.*;

public class Main
{
  public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int size = Integer.parseInt(br.readLine());
    int[] arr = new int[size];
    int j=0;
    StringTokenizer tokenizer1 = new StringTokenizer(br.readLine());
    while(tokenizer1.hasMoreTokens())
    {
      arr[j] = Integer.parseInt(tokenizer1.nextToken());
      j++;
    }
    
    Arrays.sort(arr);
    
    double ans = 0.0;
    ans = arr[0] + arr[1];
    int k = 1;
    for(int i=2;i<size;i++)
    {
      ans += arr[i] * Math.pow(2,k);
      k++;
    }
    double ans2 = ans/Math.pow(2,size-1);
    int ans3 = (int)ans2;
    System.out.println(ans2);
  }
} import java.util.*; util.* java import java.io.*; io.* java public class Main
{
  public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int size = Integer.parseInt(br.readLine());
    int[] arr = new int[size];
    int j=0;
    StringTokenizer tokenizer1 = new StringTokenizer(br.readLine());
    while(tokenizer1.hasMoreTokens())
    {
      arr[j] = Integer.parseInt(tokenizer1.nextToken());
      j++;
    }
    
    Arrays.sort(arr);
    
    double ans = 0.0;
    ans = arr[0] + arr[1];
    int k = 1;
    for(int i=2;i<size;i++)
    {
      ans += arr[i] * Math.pow(2,k);
      k++;
    }
    double ans2 = ans/Math.pow(2,size-1);
    int ans3 = (int)ans2;
    System.out.println(ans2);
  }
} Main public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int size = Integer.parseInt(br.readLine());
    int[] arr = new int[size];
    int j=0;
    StringTokenizer tokenizer1 = new StringTokenizer(br.readLine());
    while(tokenizer1.hasMoreTokens())
    {
      arr[j] = Integer.parseInt(tokenizer1.nextToken());
      j++;
    }
    
    Arrays.sort(arr);
    
    double ans = 0.0;
    ans = arr[0] + arr[1];
    int k = 1;
    for(int i=2;i<size;i++)
    {
      ans += arr[i] * Math.pow(2,k);
      k++;
    }
    double ans2 = ans/Math.pow(2,size-1);
    int ans3 = (int)ans2;
    System.out.println(ans2);
  } main {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int size = Integer.parseInt(br.readLine());
    int[] arr = new int[size];
    int j=0;
    StringTokenizer tokenizer1 = new StringTokenizer(br.readLine());
    while(tokenizer1.hasMoreTokens())
    {
      arr[j] = Integer.parseInt(tokenizer1.nextToken());
      j++;
    }
    
    Arrays.sort(arr);
    
    double ans = 0.0;
    ans = arr[0] + arr[1];
    int k = 1;
    for(int i=2;i<size;i++)
    {
      ans += arr[i] * Math.pow(2,k);
      k++;
    }
    double ans2 = ans/Math.pow(2,size-1);
    int ans3 = (int)ans2;
    System.out.println(ans2);
  } BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) int size = Integer.parseInt(br.readLine()); size Integer.parseInt(br.readLine()) Integer.parseInt Integer br.readLine() br.readLine br int[] arr = new int[size]; arr new int[size] size int j=0; j 0 StringTokenizer tokenizer1 = new StringTokenizer(br.readLine()); tokenizer1 new StringTokenizer(br.readLine()) while(tokenizer1.hasMoreTokens())
    {
      arr[j] = Integer.parseInt(tokenizer1.nextToken());
      j++;
    } tokenizer1.hasMoreTokens() tokenizer1.hasMoreTokens tokenizer1 {
      arr[j] = Integer.parseInt(tokenizer1.nextToken());
      j++;
    } arr[j] = Integer.parseInt(tokenizer1.nextToken()) arr[j] arr j Integer.parseInt(tokenizer1.nextToken()) Integer.parseInt Integer tokenizer1.nextToken() tokenizer1.nextToken tokenizer1 j++ j Arrays.sort(arr) Arrays.sort Arrays arr double ans = 0.0; ans 0.0 ans = arr[0] + arr[1] ans arr[0] + arr[1] arr[0] arr 0 arr[1] arr 1 int k = 1; k 1 for(int i=2;i<size;i++)
    {
      ans += arr[i] * Math.pow(2,k);
      k++;
    } int i=2; int i=2; i 2 i<size i size i++ i++ i {
      ans += arr[i] * Math.pow(2,k);
      k++;
    } {
      ans += arr[i] * Math.pow(2,k);
      k++;
    } ans += arr[i] * Math.pow(2,k) ans arr[i] * Math.pow(2,k) arr[i] arr i Math.pow(2,k) Math.pow Math 2 k k++ k double ans2 = ans/Math.pow(2,size-1); ans2 ans/Math.pow(2,size-1) ans Math.pow(2,size-1) Math.pow Math 2 size-1 size 1 int ans3 = (int)ans2; ans3 (int)ans2 System.out.println(ans2) System.out.println System.out System System.out ans2 String args[] args public class Main
{
  public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int size = Integer.parseInt(br.readLine());
    int[] arr = new int[size];
    int j=0;
    StringTokenizer tokenizer1 = new StringTokenizer(br.readLine());
    while(tokenizer1.hasMoreTokens())
    {
      arr[j] = Integer.parseInt(tokenizer1.nextToken());
      j++;
    }
    
    Arrays.sort(arr);
    
    double ans = 0.0;
    ans = arr[0] + arr[1];
    int k = 1;
    for(int i=2;i<size;i++)
    {
      ans += arr[i] * Math.pow(2,k);
      k++;
    }
    double ans2 = ans/Math.pow(2,size-1);
    int ans3 = (int)ans2;
    System.out.println(ans2);
  }
} public class Main
{
  public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int size = Integer.parseInt(br.readLine());
    int[] arr = new int[size];
    int j=0;
    StringTokenizer tokenizer1 = new StringTokenizer(br.readLine());
    while(tokenizer1.hasMoreTokens())
    {
      arr[j] = Integer.parseInt(tokenizer1.nextToken());
      j++;
    }
    
    Arrays.sort(arr);
    
    double ans = 0.0;
    ans = arr[0] + arr[1];
    int k = 1;
    for(int i=2;i<size;i++)
    {
      ans += arr[i] * Math.pow(2,k);
      k++;
    }
    double ans2 = ans/Math.pow(2,size-1);
    int ans3 = (int)ans2;
    System.out.println(ans2);
  }
} Main
import java.util.*;
import java.io.*;

public class Main
{
  public static void main(String args[])throws IOException
  {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    int size = Integer.parseInt(br.readLine());
    int[] arr = new int[size];
    int j=0;
    StringTokenizer tokenizer1 = new StringTokenizer(br.readLine());
    while(tokenizer1.hasMoreTokens())
    {
      arr[j] = Integer.parseInt(tokenizer1.nextToken());
      j++;
    }
    
    Arrays.sort(arr);
    
    double ans = 0.0;
    ans = arr[0] + arr[1];
    int k = 1;
    for(int i=2;i<size;i++)
    {
      ans += arr[i] * Math.pow(2,k);
      k++;
    }
    double ans2 = ans/Math.pow(2,size-1);
    int ans3 = (int)ans2;
    System.out.println(ans2);
  }
}