import java.util.Scanner;
import java.util.Arrays;
public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int[] b = new int[a];
    for(int i = 0;i < b.length;i++){
      b[i] = sc.nextInt();
    }
    Arrays.sort(b);
    double c = (double)(b[0] + b[1]) / 2;
    for(int j = 2; j < b.length; j++){
      c = (double)(c + b[j]) / 2;
    }
    System.out.println(c);
  }
} import java.util.Scanner; Scanner java.util import java.util.Arrays; Arrays java.util public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int[] b = new int[a];
    for(int i = 0;i < b.length;i++){
      b[i] = sc.nextInt();
    }
    Arrays.sort(b);
    double c = (double)(b[0] + b[1]) / 2;
    for(int j = 2; j < b.length; j++){
      c = (double)(c + b[j]) / 2;
    }
    System.out.println(c);
  }
} Main public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int[] b = new int[a];
    for(int i = 0;i < b.length;i++){
      b[i] = sc.nextInt();
    }
    Arrays.sort(b);
    double c = (double)(b[0] + b[1]) / 2;
    for(int j = 2; j < b.length; j++){
      c = (double)(c + b[j]) / 2;
    }
    System.out.println(c);
  } main {
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int[] b = new int[a];
    for(int i = 0;i < b.length;i++){
      b[i] = sc.nextInt();
    }
    Arrays.sort(b);
    double c = (double)(b[0] + b[1]) / 2;
    for(int j = 2; j < b.length; j++){
      c = (double)(c + b[j]) / 2;
    }
    System.out.println(c);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int[] b = new int[a]; b new int[a] a for(int i = 0;i < b.length;i++){
      b[i] = sc.nextInt();
    } int i = 0; int i = 0; i 0 i < b.length i b.length b b.length i++ i++ i {
      b[i] = sc.nextInt();
    } {
      b[i] = sc.nextInt();
    } b[i] = sc.nextInt() b[i] b i sc.nextInt() sc.nextInt sc Arrays.sort(b) Arrays.sort Arrays b double c = (double)(b[0] + b[1]) / 2; c (double)(b[0] + b[1]) / 2 (double)(b[0] + b[1]) b[0] b 0 b[1] b 1 2 for(int j = 2; j < b.length; j++){
      c = (double)(c + b[j]) / 2;
    } int j = 2; int j = 2; j 2 j < b.length j b.length b b.length j++ j++ j {
      c = (double)(c + b[j]) / 2;
    } {
      c = (double)(c + b[j]) / 2;
    } c = (double)(c + b[j]) / 2 c (double)(c + b[j]) / 2 (double)(c + b[j]) c b[j] b j 2 System.out.println(c) System.out.println System.out System System.out c String args[] args public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int[] b = new int[a];
    for(int i = 0;i < b.length;i++){
      b[i] = sc.nextInt();
    }
    Arrays.sort(b);
    double c = (double)(b[0] + b[1]) / 2;
    for(int j = 2; j < b.length; j++){
      c = (double)(c + b[j]) / 2;
    }
    System.out.println(c);
  }
} public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int[] b = new int[a];
    for(int i = 0;i < b.length;i++){
      b[i] = sc.nextInt();
    }
    Arrays.sort(b);
    double c = (double)(b[0] + b[1]) / 2;
    for(int j = 2; j < b.length; j++){
      c = (double)(c + b[j]) / 2;
    }
    System.out.println(c);
  }
} Main
import java.util.Scanner;
import java.util.Arrays;
public class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int[] b = new int[a];
    for(int i = 0;i < b.length;i++){
      b[i] = sc.nextInt();
    }
    Arrays.sort(b);
    double c = (double)(b[0] + b[1]) / 2;
    for(int j = 2; j < b.length; j++){
      c = (double)(c + b[j]) / 2;
    }
    System.out.println(c);
  }
}