import java.util.Arrays;
import java.util.Scanner;
public class Main { 
    public static void main(String[] args) { 
	Scanner scn = new Scanner(System.in);
        int n = scn.nextInt();
        double[]a = new double[n];
        for(int i = 0; i < n; i++){
            a[i] = scn.nextDouble();
        }
        Arrays.sort(a);
        double max = 0l;
        for(int i = 0; i < n-1; i++){
            a[i+1] = (a[i]+a[i+1])/2;
            max = a[i+1];
        }
        System.out.println(max);
    }
}  import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main { 
    public static void main(String[] args) { 
	Scanner scn = new Scanner(System.in);
        int n = scn.nextInt();
        double[]a = new double[n];
        for(int i = 0; i < n; i++){
            a[i] = scn.nextDouble();
        }
        Arrays.sort(a);
        double max = 0l;
        for(int i = 0; i < n-1; i++){
            a[i+1] = (a[i]+a[i+1])/2;
            max = a[i+1];
        }
        System.out.println(max);
    }
} Main public static void main(String[] args) { 
	Scanner scn = new Scanner(System.in);
        int n = scn.nextInt();
        double[]a = new double[n];
        for(int i = 0; i < n; i++){
            a[i] = scn.nextDouble();
        }
        Arrays.sort(a);
        double max = 0l;
        for(int i = 0; i < n-1; i++){
            a[i+1] = (a[i]+a[i+1])/2;
            max = a[i+1];
        }
        System.out.println(max);
    } main { 
	Scanner scn = new Scanner(System.in);
        int n = scn.nextInt();
        double[]a = new double[n];
        for(int i = 0; i < n; i++){
            a[i] = scn.nextDouble();
        }
        Arrays.sort(a);
        double max = 0l;
        for(int i = 0; i < n-1; i++){
            a[i+1] = (a[i]+a[i+1])/2;
            max = a[i+1];
        }
        System.out.println(max);
    } Scanner scn = new Scanner(System.in); scn new Scanner(System.in) int n = scn.nextInt(); n scn.nextInt() scn.nextInt scn double[]a = new double[n]; a new double[n] n for(int i = 0; i < n; i++){
            a[i] = scn.nextDouble();
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            a[i] = scn.nextDouble();
        } {
            a[i] = scn.nextDouble();
        } a[i] = scn.nextDouble() a[i] a i scn.nextDouble() scn.nextDouble scn Arrays.sort(a) Arrays.sort Arrays a double max = 0l; max 0l for(int i = 0; i < n-1; i++){
            a[i+1] = (a[i]+a[i+1])/2;
            max = a[i+1];
        } int i = 0; int i = 0; i 0 i < n-1 i n-1 n 1 i++ i++ i {
            a[i+1] = (a[i]+a[i+1])/2;
            max = a[i+1];
        } {
            a[i+1] = (a[i]+a[i+1])/2;
            max = a[i+1];
        } a[i+1] = (a[i]+a[i+1])/2 a[i+1] a i+1 i 1 (a[i]+a[i+1])/2 (a[i]+a[i+1]) a[i] a i a[i+1] a i+1 i 1 2 max = a[i+1] max a[i+1] a i+1 i 1 System.out.println(max) System.out.println System.out System System.out max String[] args args public class Main { 
    public static void main(String[] args) { 
	Scanner scn = new Scanner(System.in);
        int n = scn.nextInt();
        double[]a = new double[n];
        for(int i = 0; i < n; i++){
            a[i] = scn.nextDouble();
        }
        Arrays.sort(a);
        double max = 0l;
        for(int i = 0; i < n-1; i++){
            a[i+1] = (a[i]+a[i+1])/2;
            max = a[i+1];
        }
        System.out.println(max);
    }
} public class Main { 
    public static void main(String[] args) { 
	Scanner scn = new Scanner(System.in);
        int n = scn.nextInt();
        double[]a = new double[n];
        for(int i = 0; i < n; i++){
            a[i] = scn.nextDouble();
        }
        Arrays.sort(a);
        double max = 0l;
        for(int i = 0; i < n-1; i++){
            a[i+1] = (a[i]+a[i+1])/2;
            max = a[i+1];
        }
        System.out.println(max);
    }
} Main
import java.util.Arrays;
import java.util.Scanner;
public class Main { 
    public static void main(String[] args) { 
	Scanner scn = new Scanner(System.in);
        int n = scn.nextInt();
        double[]a = new double[n];
        for(int i = 0; i < n; i++){
            a[i] = scn.nextDouble();
        }
        Arrays.sort(a);
        double max = 0l;
        for(int i = 0; i < n-1; i++){
            a[i+1] = (a[i]+a[i+1])/2;
            max = a[i+1];
        }
        System.out.println(max);
    }
} 
