import java.util.*;
public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    LinkedList<Double> material = new LinkedList<Double>();
    for(int i = 0; i < n; i++){
      material.add(sc.nextDouble());
    }
    
    while(material.size() > 1){
      //降順にソートしてから前2つを取り出し生成物を1つプッシュ
      Collections.sort(material);
      material.add((material.pollFirst() + material.pollFirst()) / 2);
    }
    
    System.out.println(material.peek());
  }
  
} import java.util.*; util.* java public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    LinkedList<Double> material = new LinkedList<Double>();
    for(int i = 0; i < n; i++){
      material.add(sc.nextDouble());
    }
    
    while(material.size() > 1){
      //降順にソートしてから前2つを取り出し生成物を1つプッシュ
      Collections.sort(material);
      material.add((material.pollFirst() + material.pollFirst()) / 2);
    }
    
    System.out.println(material.peek());
  }
  
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    LinkedList<Double> material = new LinkedList<Double>();
    for(int i = 0; i < n; i++){
      material.add(sc.nextDouble());
    }
    
    while(material.size() > 1){
      //降順にソートしてから前2つを取り出し生成物を1つプッシュ
      Collections.sort(material);
      material.add((material.pollFirst() + material.pollFirst()) / 2);
    }
    
    System.out.println(material.peek());
  } main {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    LinkedList<Double> material = new LinkedList<Double>();
    for(int i = 0; i < n; i++){
      material.add(sc.nextDouble());
    }
    
    while(material.size() > 1){
      //降順にソートしてから前2つを取り出し生成物を1つプッシュ
      Collections.sort(material);
      material.add((material.pollFirst() + material.pollFirst()) / 2);
    }
    
    System.out.println(material.peek());
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc LinkedList<Double> material = new LinkedList<Double>(); material new LinkedList<Double>() for(int i = 0; i < n; i++){
      material.add(sc.nextDouble());
    } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
      material.add(sc.nextDouble());
    } {
      material.add(sc.nextDouble());
    } material.add(sc.nextDouble()) material.add material sc.nextDouble() sc.nextDouble sc while(material.size() > 1){
      //降順にソートしてから前2つを取り出し生成物を1つプッシュ
      Collections.sort(material);
      material.add((material.pollFirst() + material.pollFirst()) / 2);
    } material.size() > 1 material.size() material.size material 1 {
      //降順にソートしてから前2つを取り出し生成物を1つプッシュ
      Collections.sort(material);
      material.add((material.pollFirst() + material.pollFirst()) / 2);
    } Collections.sort(material) Collections.sort Collections material material.add((material.pollFirst() + material.pollFirst()) / 2) material.add material (material.pollFirst() + material.pollFirst()) / 2 (material.pollFirst() + material.pollFirst()) material.pollFirst() material.pollFirst material material.pollFirst() material.pollFirst material 2 System.out.println(material.peek()) System.out.println System.out System System.out material.peek() material.peek material String[] args args public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    LinkedList<Double> material = new LinkedList<Double>();
    for(int i = 0; i < n; i++){
      material.add(sc.nextDouble());
    }
    
    while(material.size() > 1){
      //降順にソートしてから前2つを取り出し生成物を1つプッシュ
      Collections.sort(material);
      material.add((material.pollFirst() + material.pollFirst()) / 2);
    }
    
    System.out.println(material.peek());
  }
  
} public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    LinkedList<Double> material = new LinkedList<Double>();
    for(int i = 0; i < n; i++){
      material.add(sc.nextDouble());
    }
    
    while(material.size() > 1){
      //降順にソートしてから前2つを取り出し生成物を1つプッシュ
      Collections.sort(material);
      material.add((material.pollFirst() + material.pollFirst()) / 2);
    }
    
    System.out.println(material.peek());
  }
  
} Main
import java.util.*;
public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    LinkedList<Double> material = new LinkedList<Double>();
    for(int i = 0; i < n; i++){
      material.add(sc.nextDouble());
    }
    
    while(material.size() > 1){
      //降順にソートしてから前2つを取り出し生成物を1つプッシュ
      Collections.sort(material);
      material.add((material.pollFirst() + material.pollFirst()) / 2);
    }
    
    System.out.println(material.peek());
  }
  
}