import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    ArrayList<Double> list = new ArrayList<Double>();

    for (int i = 0; i < n; i++) {
      list.add(sc.nextDouble());
    }

    for (int i = 0; i < (n - 1); i++) {
      Collections.sort(list);
      list.add((list.get(0) + list.get(1)) / 2);
      list.remove(0);
      list.remove(0);
    }

    System.out.println(list.get(0));

  }
} import java.util.ArrayList; ArrayList java.util import java.util.Collections; Collections java.util import java.util.Scanner; Scanner java.util public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    ArrayList<Double> list = new ArrayList<Double>();

    for (int i = 0; i < n; i++) {
      list.add(sc.nextDouble());
    }

    for (int i = 0; i < (n - 1); i++) {
      Collections.sort(list);
      list.add((list.get(0) + list.get(1)) / 2);
      list.remove(0);
      list.remove(0);
    }

    System.out.println(list.get(0));

  }
} Main public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    ArrayList<Double> list = new ArrayList<Double>();

    for (int i = 0; i < n; i++) {
      list.add(sc.nextDouble());
    }

    for (int i = 0; i < (n - 1); i++) {
      Collections.sort(list);
      list.add((list.get(0) + list.get(1)) / 2);
      list.remove(0);
      list.remove(0);
    }

    System.out.println(list.get(0));

  } main {

    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    ArrayList<Double> list = new ArrayList<Double>();

    for (int i = 0; i < n; i++) {
      list.add(sc.nextDouble());
    }

    for (int i = 0; i < (n - 1); i++) {
      Collections.sort(list);
      list.add((list.get(0) + list.get(1)) / 2);
      list.remove(0);
      list.remove(0);
    }

    System.out.println(list.get(0));

  } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc ArrayList<Double> list = new ArrayList<Double>(); list new ArrayList<Double>() for (int i = 0; i < n; i++) {
      list.add(sc.nextDouble());
    } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
      list.add(sc.nextDouble());
    } {
      list.add(sc.nextDouble());
    } list.add(sc.nextDouble()) list.add list sc.nextDouble() sc.nextDouble sc for (int i = 0; i < (n - 1); i++) {
      Collections.sort(list);
      list.add((list.get(0) + list.get(1)) / 2);
      list.remove(0);
      list.remove(0);
    } int i = 0; int i = 0; i 0 i < (n - 1) i (n - 1) n 1 i++ i++ i {
      Collections.sort(list);
      list.add((list.get(0) + list.get(1)) / 2);
      list.remove(0);
      list.remove(0);
    } {
      Collections.sort(list);
      list.add((list.get(0) + list.get(1)) / 2);
      list.remove(0);
      list.remove(0);
    } Collections.sort(list) Collections.sort Collections list list.add((list.get(0) + list.get(1)) / 2) list.add list (list.get(0) + list.get(1)) / 2 (list.get(0) + list.get(1)) list.get(0) list.get list 0 list.get(1) list.get list 1 2 list.remove(0) list.remove list 0 list.remove(0) list.remove list 0 System.out.println(list.get(0)) System.out.println System.out System System.out list.get(0) list.get list 0 String[] args args public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    ArrayList<Double> list = new ArrayList<Double>();

    for (int i = 0; i < n; i++) {
      list.add(sc.nextDouble());
    }

    for (int i = 0; i < (n - 1); i++) {
      Collections.sort(list);
      list.add((list.get(0) + list.get(1)) / 2);
      list.remove(0);
      list.remove(0);
    }

    System.out.println(list.get(0));

  }
} public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    ArrayList<Double> list = new ArrayList<Double>();

    for (int i = 0; i < n; i++) {
      list.add(sc.nextDouble());
    }

    for (int i = 0; i < (n - 1); i++) {
      Collections.sort(list);
      list.add((list.get(0) + list.get(1)) / 2);
      list.remove(0);
      list.remove(0);
    }

    System.out.println(list.get(0));

  }
} Main
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class Main {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    ArrayList<Double> list = new ArrayList<Double>();

    for (int i = 0; i < n; i++) {
      list.add(sc.nextDouble());
    }

    for (int i = 0; i < (n - 1); i++) {
      Collections.sort(list);
      list.add((list.get(0) + list.get(1)) / 2);
      list.remove(0);
      list.remove(0);
    }

    System.out.println(list.get(0));

  }
}