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

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Integer> list = new ArrayList<>();
        for(int i=0; i<n; i++) {
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        double total = (list.get(0) + list.get(1)) / 2.0;
        for(int i=2; i<n; i++) {
            total = (list.get(i) + total) / 2.0;
        }
        System.out.println(total);
    }
} import java.util.ArrayList; ArrayList java.util import java.util.Collections; Collections java.util import java.util.List; List 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();
        List<Integer> list = new ArrayList<>();
        for(int i=0; i<n; i++) {
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        double total = (list.get(0) + list.get(1)) / 2.0;
        for(int i=2; i<n; i++) {
            total = (list.get(i) + total) / 2.0;
        }
        System.out.println(total);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Integer> list = new ArrayList<>();
        for(int i=0; i<n; i++) {
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        double total = (list.get(0) + list.get(1)) / 2.0;
        for(int i=2; i<n; i++) {
            total = (list.get(i) + total) / 2.0;
        }
        System.out.println(total);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Integer> list = new ArrayList<>();
        for(int i=0; i<n; i++) {
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        double total = (list.get(0) + list.get(1)) / 2.0;
        for(int i=2; i<n; i++) {
            total = (list.get(i) + total) / 2.0;
        }
        System.out.println(total);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc List<Integer> list = new ArrayList<>(); list new ArrayList<>() for(int i=0; i<n; i++) {
            list.add(sc.nextInt());
        } int i=0; int i=0; i 0 i<n i n i++ i++ i {
            list.add(sc.nextInt());
        } {
            list.add(sc.nextInt());
        } list.add(sc.nextInt()) list.add list sc.nextInt() sc.nextInt sc Collections.sort(list) Collections.sort Collections list double total = (list.get(0) + list.get(1)) / 2.0; total (list.get(0) + list.get(1)) / 2.0 (list.get(0) + list.get(1)) list.get(0) list.get list 0 list.get(1) list.get list 1 2.0 for(int i=2; i<n; i++) {
            total = (list.get(i) + total) / 2.0;
        } int i=2; int i=2; i 2 i<n i n i++ i++ i {
            total = (list.get(i) + total) / 2.0;
        } {
            total = (list.get(i) + total) / 2.0;
        } total = (list.get(i) + total) / 2.0 total (list.get(i) + total) / 2.0 (list.get(i) + total) list.get(i) list.get list i total 2.0 System.out.println(total) System.out.println System.out System System.out total String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Integer> list = new ArrayList<>();
        for(int i=0; i<n; i++) {
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        double total = (list.get(0) + list.get(1)) / 2.0;
        for(int i=2; i<n; i++) {
            total = (list.get(i) + total) / 2.0;
        }
        System.out.println(total);
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Integer> list = new ArrayList<>();
        for(int i=0; i<n; i++) {
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        double total = (list.get(0) + list.get(1)) / 2.0;
        for(int i=2; i<n; i++) {
            total = (list.get(i) + total) / 2.0;
        }
        System.out.println(total);
    }
} Main
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Integer> list = new ArrayList<>();
        for(int i=0; i<n; i++) {
            list.add(sc.nextInt());
        }
        Collections.sort(list);
        double total = (list.get(0) + list.get(1)) / 2.0;
        for(int i=2; i<n; i++) {
            total = (list.get(i) + total) / 2.0;
        }
        System.out.println(total);
    }
}