import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        double[] arr = new double[num];
        for (int i = 0;i < num;i++){
            arr[i] = in.nextDouble();
        }
        Arrays.sort(arr);
        for (int i = 0;i < num - 1;i++){
            arr[i+1] = (arr[i] + arr[i+1]) / 2;
        }
        
        System.out.println(arr[num - 1]);

        
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        double[] arr = new double[num];
        for (int i = 0;i < num;i++){
            arr[i] = in.nextDouble();
        }
        Arrays.sort(arr);
        for (int i = 0;i < num - 1;i++){
            arr[i+1] = (arr[i] + arr[i+1]) / 2;
        }
        
        System.out.println(arr[num - 1]);

        
    }
} Main public static void main(String[] args) throws Exception {
        // Your code here!
        
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        double[] arr = new double[num];
        for (int i = 0;i < num;i++){
            arr[i] = in.nextDouble();
        }
        Arrays.sort(arr);
        for (int i = 0;i < num - 1;i++){
            arr[i+1] = (arr[i] + arr[i+1]) / 2;
        }
        
        System.out.println(arr[num - 1]);

        
    } main {
        // Your code here!
        
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        double[] arr = new double[num];
        for (int i = 0;i < num;i++){
            arr[i] = in.nextDouble();
        }
        Arrays.sort(arr);
        for (int i = 0;i < num - 1;i++){
            arr[i+1] = (arr[i] + arr[i+1]) / 2;
        }
        
        System.out.println(arr[num - 1]);

        
    } Scanner in = new Scanner(System.in); in new Scanner(System.in) int num = in.nextInt(); num in.nextInt() in.nextInt in double[] arr = new double[num]; arr new double[num] num for (int i = 0;i < num;i++){
            arr[i] = in.nextDouble();
        } int i = 0; int i = 0; i 0 i < num i num i++ i++ i {
            arr[i] = in.nextDouble();
        } {
            arr[i] = in.nextDouble();
        } arr[i] = in.nextDouble() arr[i] arr i in.nextDouble() in.nextDouble in Arrays.sort(arr) Arrays.sort Arrays arr for (int i = 0;i < num - 1;i++){
            arr[i+1] = (arr[i] + arr[i+1]) / 2;
        } int i = 0; int i = 0; i 0 i < num - 1 i num - 1 num 1 i++ i++ i {
            arr[i+1] = (arr[i] + arr[i+1]) / 2;
        } {
            arr[i+1] = (arr[i] + arr[i+1]) / 2;
        } arr[i+1] = (arr[i] + arr[i+1]) / 2 arr[i+1] arr i+1 i 1 (arr[i] + arr[i+1]) / 2 (arr[i] + arr[i+1]) arr[i] arr i arr[i+1] arr i+1 i 1 2 System.out.println(arr[num - 1]) System.out.println System.out System System.out arr[num - 1] arr num - 1 num 1 String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        double[] arr = new double[num];
        for (int i = 0;i < num;i++){
            arr[i] = in.nextDouble();
        }
        Arrays.sort(arr);
        for (int i = 0;i < num - 1;i++){
            arr[i+1] = (arr[i] + arr[i+1]) / 2;
        }
        
        System.out.println(arr[num - 1]);

        
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        double[] arr = new double[num];
        for (int i = 0;i < num;i++){
            arr[i] = in.nextDouble();
        }
        Arrays.sort(arr);
        for (int i = 0;i < num - 1;i++){
            arr[i+1] = (arr[i] + arr[i+1]) / 2;
        }
        
        System.out.println(arr[num - 1]);

        
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        // Your code here!
        
        Scanner in = new Scanner(System.in);
        int num = in.nextInt();
        double[] arr = new double[num];
        for (int i = 0;i < num;i++){
            arr[i] = in.nextDouble();
        }
        Arrays.sort(arr);
        for (int i = 0;i < num - 1;i++){
            arr[i+1] = (arr[i] + arr[i+1]) / 2;
        }
        
        System.out.println(arr[num - 1]);

        
    }
}
