import java.util.*;

class Main {
  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();

    List<Double> v = new ArrayList<Double>();
    for(int i = 0; i < n; i++) v.add(scan.nextDouble());

    Collections.sort(v);
    for(int i = 0; i < n - 1; i++) {
      double x = (double)v.get(0);
      double y = (double)v.get(1);
      x = (x + y) / 2.0;
      v.set(0, x);
      v.remove(1);
    }

    System.out.println(v.get(0));
  }
} import java.util.*; util.* java class Main {
  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();

    List<Double> v = new ArrayList<Double>();
    for(int i = 0; i < n; i++) v.add(scan.nextDouble());

    Collections.sort(v);
    for(int i = 0; i < n - 1; i++) {
      double x = (double)v.get(0);
      double y = (double)v.get(1);
      x = (x + y) / 2.0;
      v.set(0, x);
      v.remove(1);
    }

    System.out.println(v.get(0));
  }
} Main public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();

    List<Double> v = new ArrayList<Double>();
    for(int i = 0; i < n; i++) v.add(scan.nextDouble());

    Collections.sort(v);
    for(int i = 0; i < n - 1; i++) {
      double x = (double)v.get(0);
      double y = (double)v.get(1);
      x = (x + y) / 2.0;
      v.set(0, x);
      v.remove(1);
    }

    System.out.println(v.get(0));
  } main {
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();

    List<Double> v = new ArrayList<Double>();
    for(int i = 0; i < n; i++) v.add(scan.nextDouble());

    Collections.sort(v);
    for(int i = 0; i < n - 1; i++) {
      double x = (double)v.get(0);
      double y = (double)v.get(1);
      x = (x + y) / 2.0;
      v.set(0, x);
      v.remove(1);
    }

    System.out.println(v.get(0));
  } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int n = scan.nextInt(); n scan.nextInt() scan.nextInt scan List<Double> v = new ArrayList<Double>(); v new ArrayList<Double>() for(int i = 0; i < n; i++) v.add(scan.nextDouble()); int i = 0; int i = 0; i 0 i < n i n i++ i++ i v.add(scan.nextDouble()); v.add(scan.nextDouble()) v.add v scan.nextDouble() scan.nextDouble scan Collections.sort(v) Collections.sort Collections v for(int i = 0; i < n - 1; i++) {
      double x = (double)v.get(0);
      double y = (double)v.get(1);
      x = (x + y) / 2.0;
      v.set(0, x);
      v.remove(1);
    } int i = 0; int i = 0; i 0 i < n - 1 i n - 1 n 1 i++ i++ i {
      double x = (double)v.get(0);
      double y = (double)v.get(1);
      x = (x + y) / 2.0;
      v.set(0, x);
      v.remove(1);
    } {
      double x = (double)v.get(0);
      double y = (double)v.get(1);
      x = (x + y) / 2.0;
      v.set(0, x);
      v.remove(1);
    } double x = (double)v.get(0); x (double)v.get(0) v.get v 0 double y = (double)v.get(1); y (double)v.get(1) v.get v 1 x = (x + y) / 2.0 x (x + y) / 2.0 (x + y) x y 2.0 v.set(0, x) v.set v 0 x v.remove(1) v.remove v 1 System.out.println(v.get(0)) System.out.println System.out System System.out v.get(0) v.get v 0 String[] args args
import java.util.*;

class Main {
  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();

    List<Double> v = new ArrayList<Double>();
    for(int i = 0; i < n; i++) v.add(scan.nextDouble());

    Collections.sort(v);
    for(int i = 0; i < n - 1; i++) {
      double x = (double)v.get(0);
      double y = (double)v.get(1);
      x = (x + y) / 2.0;
      v.set(0, x);
      v.remove(1);
    }

    System.out.println(v.get(0));
  }
}