import java.util.*;

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

    int n = sc.nextInt();
    
    Double[] v = new Double[n];
    List<Double> gu = new ArrayList<>();
    for (int i = 0; i < n; i++) {
      v[i] = sc.nextDouble();
      gu.add(v[i]);
    }

    for (int i = 0; i < n - 1; i++) {
      Collections.sort(gu);
      double a = (gu.get(0) + gu.get(1)) / 2;
      gu.add(a);
      gu.remove(0);
      gu.remove(0);
    }
    
    System.out.println(gu.get(0));
    
  }
} import java.util.*; util.* java public class Main {
  public static void main (String[] args) {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    
    Double[] v = new Double[n];
    List<Double> gu = new ArrayList<>();
    for (int i = 0; i < n; i++) {
      v[i] = sc.nextDouble();
      gu.add(v[i]);
    }

    for (int i = 0; i < n - 1; i++) {
      Collections.sort(gu);
      double a = (gu.get(0) + gu.get(1)) / 2;
      gu.add(a);
      gu.remove(0);
      gu.remove(0);
    }
    
    System.out.println(gu.get(0));
    
  }
} Main public static void main (String[] args) {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    
    Double[] v = new Double[n];
    List<Double> gu = new ArrayList<>();
    for (int i = 0; i < n; i++) {
      v[i] = sc.nextDouble();
      gu.add(v[i]);
    }

    for (int i = 0; i < n - 1; i++) {
      Collections.sort(gu);
      double a = (gu.get(0) + gu.get(1)) / 2;
      gu.add(a);
      gu.remove(0);
      gu.remove(0);
    }
    
    System.out.println(gu.get(0));
    
  } main {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    
    Double[] v = new Double[n];
    List<Double> gu = new ArrayList<>();
    for (int i = 0; i < n; i++) {
      v[i] = sc.nextDouble();
      gu.add(v[i]);
    }

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

    int n = sc.nextInt();
    
    Double[] v = new Double[n];
    List<Double> gu = new ArrayList<>();
    for (int i = 0; i < n; i++) {
      v[i] = sc.nextDouble();
      gu.add(v[i]);
    }

    for (int i = 0; i < n - 1; i++) {
      Collections.sort(gu);
      double a = (gu.get(0) + gu.get(1)) / 2;
      gu.add(a);
      gu.remove(0);
      gu.remove(0);
    }
    
    System.out.println(gu.get(0));
    
  }
} public class Main {
  public static void main (String[] args) {
    Scanner sc = new Scanner(System.in);

    int n = sc.nextInt();
    
    Double[] v = new Double[n];
    List<Double> gu = new ArrayList<>();
    for (int i = 0; i < n; i++) {
      v[i] = sc.nextDouble();
      gu.add(v[i]);
    }

    for (int i = 0; i < n - 1; i++) {
      Collections.sort(gu);
      double a = (gu.get(0) + gu.get(1)) / 2;
      gu.add(a);
      gu.remove(0);
      gu.remove(0);
    }
    
    System.out.println(gu.get(0));
    
  }
} Main
import java.util.*;

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

    int n = sc.nextInt();
    
    Double[] v = new Double[n];
    List<Double> gu = new ArrayList<>();
    for (int i = 0; i < n; i++) {
      v[i] = sc.nextDouble();
      gu.add(v[i]);
    }

    for (int i = 0; i < n - 1; i++) {
      Collections.sort(gu);
      double a = (gu.get(0) + gu.get(1)) / 2;
      gu.add(a);
      gu.remove(0);
      gu.remove(0);
    }
    
    System.out.println(gu.get(0));
    
  }
}
