import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int a;
    Integer[] array = new Integer[n];
    double sum = 0;

    for(int i=0; i<n; i++){
      a = sc.nextInt();
      array[i] = a;
    }
    Arrays.sort(array,Comparator.reverseOrder());
    //for(int k=0; k<n; k++){
      //System.out.println(array[k]);
    //}
    for(int k=0; k<n-1; k++ ){
      double sub_sum = array[k]/Math.pow(2,k+1) ;
      sum += sub_sum;
      //System.out.println("sum:"+sum);
    }
    sum += array[n-1]/Math.pow(2,n-1);
    System.out.println(sum);
  }
} import java.util.*; util.* java public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int a;
    Integer[] array = new Integer[n];
    double sum = 0;

    for(int i=0; i<n; i++){
      a = sc.nextInt();
      array[i] = a;
    }
    Arrays.sort(array,Comparator.reverseOrder());
    //for(int k=0; k<n; k++){
      //System.out.println(array[k]);
    //}
    for(int k=0; k<n-1; k++ ){
      double sub_sum = array[k]/Math.pow(2,k+1) ;
      sum += sub_sum;
      //System.out.println("sum:"+sum);
    }
    sum += array[n-1]/Math.pow(2,n-1);
    System.out.println(sum);
  }
} Main public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int a;
    Integer[] array = new Integer[n];
    double sum = 0;

    for(int i=0; i<n; i++){
      a = sc.nextInt();
      array[i] = a;
    }
    Arrays.sort(array,Comparator.reverseOrder());
    //for(int k=0; k<n; k++){
      //System.out.println(array[k]);
    //}
    for(int k=0; k<n-1; k++ ){
      double sub_sum = array[k]/Math.pow(2,k+1) ;
      sum += sub_sum;
      //System.out.println("sum:"+sum);
    }
    sum += array[n-1]/Math.pow(2,n-1);
    System.out.println(sum);
  } main {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int a;
    Integer[] array = new Integer[n];
    double sum = 0;

    for(int i=0; i<n; i++){
      a = sc.nextInt();
      array[i] = a;
    }
    Arrays.sort(array,Comparator.reverseOrder());
    //for(int k=0; k<n; k++){
      //System.out.println(array[k]);
    //}
    for(int k=0; k<n-1; k++ ){
      double sub_sum = array[k]/Math.pow(2,k+1) ;
      sum += sub_sum;
      //System.out.println("sum:"+sum);
    }
    sum += array[n-1]/Math.pow(2,n-1);
    System.out.println(sum);
  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int a; a Integer[] array = new Integer[n]; array new Integer[n] n double sum = 0; sum 0 for(int i=0; i<n; i++){
      a = sc.nextInt();
      array[i] = a;
    } int i=0; int i=0; i 0 i<n i n i++ i++ i {
      a = sc.nextInt();
      array[i] = a;
    } {
      a = sc.nextInt();
      array[i] = a;
    } a = sc.nextInt() a sc.nextInt() sc.nextInt sc array[i] = a array[i] array i a Arrays.sort(array,Comparator.reverseOrder()) Arrays.sort Arrays array Comparator.reverseOrder() Comparator.reverseOrder Comparator for(int k=0; k<n-1; k++ ){
      double sub_sum = array[k]/Math.pow(2,k+1) ;
      sum += sub_sum;
      //System.out.println("sum:"+sum);
    } int k=0; int k=0; k 0 k<n-1 k n-1 n 1 k++ k++ k {
      double sub_sum = array[k]/Math.pow(2,k+1) ;
      sum += sub_sum;
      //System.out.println("sum:"+sum);
    } {
      double sub_sum = array[k]/Math.pow(2,k+1) ;
      sum += sub_sum;
      //System.out.println("sum:"+sum);
    } double sub_sum = array[k]/Math.pow(2,k+1) ; sub_sum array[k]/Math.pow(2,k+1) array[k] array k Math.pow(2,k+1) Math.pow Math 2 k+1 k 1 sum += sub_sum sum sub_sum sum += array[n-1]/Math.pow(2,n-1) sum array[n-1]/Math.pow(2,n-1) array[n-1] array n-1 n 1 Math.pow(2,n-1) Math.pow Math 2 n-1 n 1 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 sc = new Scanner(System.in);
    int n = sc.nextInt();
    int a;
    Integer[] array = new Integer[n];
    double sum = 0;

    for(int i=0; i<n; i++){
      a = sc.nextInt();
      array[i] = a;
    }
    Arrays.sort(array,Comparator.reverseOrder());
    //for(int k=0; k<n; k++){
      //System.out.println(array[k]);
    //}
    for(int k=0; k<n-1; k++ ){
      double sub_sum = array[k]/Math.pow(2,k+1) ;
      sum += sub_sum;
      //System.out.println("sum:"+sum);
    }
    sum += array[n-1]/Math.pow(2,n-1);
    System.out.println(sum);
  }
} public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int a;
    Integer[] array = new Integer[n];
    double sum = 0;

    for(int i=0; i<n; i++){
      a = sc.nextInt();
      array[i] = a;
    }
    Arrays.sort(array,Comparator.reverseOrder());
    //for(int k=0; k<n; k++){
      //System.out.println(array[k]);
    //}
    for(int k=0; k<n-1; k++ ){
      double sub_sum = array[k]/Math.pow(2,k+1) ;
      sum += sub_sum;
      //System.out.println("sum:"+sum);
    }
    sum += array[n-1]/Math.pow(2,n-1);
    System.out.println(sum);
  }
} Main
import java.util.*;

public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    int a;
    Integer[] array = new Integer[n];
    double sum = 0;

    for(int i=0; i<n; i++){
      a = sc.nextInt();
      array[i] = a;
    }
    Arrays.sort(array,Comparator.reverseOrder());
    //for(int k=0; k<n; k++){
      //System.out.println(array[k]);
    //}
    for(int k=0; k<n-1; k++ ){
      double sub_sum = array[k]/Math.pow(2,k+1) ;
      sum += sub_sum;
      //System.out.println("sum:"+sum);
    }
    sum += array[n-1]/Math.pow(2,n-1);
    System.out.println(sum);
  }
}