import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();
    int[] a = new int[n];
    for (int i=0;i<n;i++){
      a[i] = scan.nextInt();
    }
    Arrays.sort(a);
    long gg = (long) Math.pow(2,n-1);
    double sum = (double) a[0]/gg;
    for (int j=1;j<n;j++){
      long power = (long) Math.pow(2,n-j);
      sum += (double) a[j]/power;
    }
    System.out.println(sum);

  }
} import java.util.*; util.* java public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();
    int[] a = new int[n];
    for (int i=0;i<n;i++){
      a[i] = scan.nextInt();
    }
    Arrays.sort(a);
    long gg = (long) Math.pow(2,n-1);
    double sum = (double) a[0]/gg;
    for (int j=1;j<n;j++){
      long power = (long) Math.pow(2,n-j);
      sum += (double) a[j]/power;
    }
    System.out.println(sum);

  }
} Main public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();
    int[] a = new int[n];
    for (int i=0;i<n;i++){
      a[i] = scan.nextInt();
    }
    Arrays.sort(a);
    long gg = (long) Math.pow(2,n-1);
    double sum = (double) a[0]/gg;
    for (int j=1;j<n;j++){
      long power = (long) Math.pow(2,n-j);
      sum += (double) a[j]/power;
    }
    System.out.println(sum);

  } main {
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();
    int[] a = new int[n];
    for (int i=0;i<n;i++){
      a[i] = scan.nextInt();
    }
    Arrays.sort(a);
    long gg = (long) Math.pow(2,n-1);
    double sum = (double) a[0]/gg;
    for (int j=1;j<n;j++){
      long power = (long) Math.pow(2,n-j);
      sum += (double) a[j]/power;
    }
    System.out.println(sum);

  } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int n = scan.nextInt(); n scan.nextInt() scan.nextInt scan int[] a = new int[n]; a new int[n] n for (int i=0;i<n;i++){
      a[i] = scan.nextInt();
    } int i=0; int i=0; i 0 i<n i n i++ i++ i {
      a[i] = scan.nextInt();
    } {
      a[i] = scan.nextInt();
    } a[i] = scan.nextInt() a[i] a i scan.nextInt() scan.nextInt scan Arrays.sort(a) Arrays.sort Arrays a long gg = (long) Math.pow(2,n-1); gg (long) Math.pow(2,n-1) Math.pow Math 2 n-1 n 1 double sum = (double) a[0]/gg; sum (double) a[0]/gg (double) a[0] a 0 gg for (int j=1;j<n;j++){
      long power = (long) Math.pow(2,n-j);
      sum += (double) a[j]/power;
    } int j=1; int j=1; j 1 j<n j n j++ j++ j {
      long power = (long) Math.pow(2,n-j);
      sum += (double) a[j]/power;
    } {
      long power = (long) Math.pow(2,n-j);
      sum += (double) a[j]/power;
    } long power = (long) Math.pow(2,n-j); power (long) Math.pow(2,n-j) Math.pow Math 2 n-j n j sum += (double) a[j]/power sum (double) a[j]/power (double) a[j] a j power System.out.println(sum) System.out.println System.out System System.out sum String[] args args public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();
    int[] a = new int[n];
    for (int i=0;i<n;i++){
      a[i] = scan.nextInt();
    }
    Arrays.sort(a);
    long gg = (long) Math.pow(2,n-1);
    double sum = (double) a[0]/gg;
    for (int j=1;j<n;j++){
      long power = (long) Math.pow(2,n-j);
      sum += (double) a[j]/power;
    }
    System.out.println(sum);

  }
} public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();
    int[] a = new int[n];
    for (int i=0;i<n;i++){
      a[i] = scan.nextInt();
    }
    Arrays.sort(a);
    long gg = (long) Math.pow(2,n-1);
    double sum = (double) a[0]/gg;
    for (int j=1;j<n;j++){
      long power = (long) Math.pow(2,n-j);
      sum += (double) a[j]/power;
    }
    System.out.println(sum);

  }
} Main
import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();
    int[] a = new int[n];
    for (int i=0;i<n;i++){
      a[i] = scan.nextInt();
    }
    Arrays.sort(a);
    long gg = (long) Math.pow(2,n-1);
    double sum = (double) a[0]/gg;
    for (int j=1;j<n;j++){
      long power = (long) Math.pow(2,n-j);
      sum += (double) a[j]/power;
    }
    System.out.println(sum);

  }
}
