import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        PriorityQueue<Double> queue = new PriorityQueue<>();
        for(int i=0;i<n;i++){
            queue.add((double)Integer.parseInt(sc.next()));
        }
        Double a,b;
        while(queue.size() > 1){
            a = queue.poll();
            b = queue.poll();
            queue.add((a+b)/2.0);
        }
        System.out.println(queue.poll());
        sc.close();
    }
} import java.util.PriorityQueue; PriorityQueue 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 = Integer.parseInt(sc.next());
        PriorityQueue<Double> queue = new PriorityQueue<>();
        for(int i=0;i<n;i++){
            queue.add((double)Integer.parseInt(sc.next()));
        }
        Double a,b;
        while(queue.size() > 1){
            a = queue.poll();
            b = queue.poll();
            queue.add((a+b)/2.0);
        }
        System.out.println(queue.poll());
        sc.close();
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        PriorityQueue<Double> queue = new PriorityQueue<>();
        for(int i=0;i<n;i++){
            queue.add((double)Integer.parseInt(sc.next()));
        }
        Double a,b;
        while(queue.size() > 1){
            a = queue.poll();
            b = queue.poll();
            queue.add((a+b)/2.0);
        }
        System.out.println(queue.poll());
        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        PriorityQueue<Double> queue = new PriorityQueue<>();
        for(int i=0;i<n;i++){
            queue.add((double)Integer.parseInt(sc.next()));
        }
        Double a,b;
        while(queue.size() > 1){
            a = queue.poll();
            b = queue.poll();
            queue.add((a+b)/2.0);
        }
        System.out.println(queue.poll());
        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = Integer.parseInt(sc.next()); n Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc PriorityQueue<Double> queue = new PriorityQueue<>(); queue new PriorityQueue<>() for(int i=0;i<n;i++){
            queue.add((double)Integer.parseInt(sc.next()));
        } int i=0; int i=0; i 0 i<n i n i++ i++ i {
            queue.add((double)Integer.parseInt(sc.next()));
        } {
            queue.add((double)Integer.parseInt(sc.next()));
        } queue.add((double)Integer.parseInt(sc.next())) queue.add queue (double)Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc Double a a b; b while(queue.size() > 1){
            a = queue.poll();
            b = queue.poll();
            queue.add((a+b)/2.0);
        } queue.size() > 1 queue.size() queue.size queue 1 {
            a = queue.poll();
            b = queue.poll();
            queue.add((a+b)/2.0);
        } a = queue.poll() a queue.poll() queue.poll queue b = queue.poll() b queue.poll() queue.poll queue queue.add((a+b)/2.0) queue.add queue (a+b)/2.0 (a+b) a b 2.0 System.out.println(queue.poll()) System.out.println System.out System System.out queue.poll() queue.poll queue sc.close() sc.close sc String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        PriorityQueue<Double> queue = new PriorityQueue<>();
        for(int i=0;i<n;i++){
            queue.add((double)Integer.parseInt(sc.next()));
        }
        Double a,b;
        while(queue.size() > 1){
            a = queue.poll();
            b = queue.poll();
            queue.add((a+b)/2.0);
        }
        System.out.println(queue.poll());
        sc.close();
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        PriorityQueue<Double> queue = new PriorityQueue<>();
        for(int i=0;i<n;i++){
            queue.add((double)Integer.parseInt(sc.next()));
        }
        Double a,b;
        while(queue.size() > 1){
            a = queue.poll();
            b = queue.poll();
            queue.add((a+b)/2.0);
        }
        System.out.println(queue.poll());
        sc.close();
    }
} Main
import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        PriorityQueue<Double> queue = new PriorityQueue<>();
        for(int i=0;i<n;i++){
            queue.add((double)Integer.parseInt(sc.next()));
        }
        Double a,b;
        while(queue.size() > 1){
            a = queue.poll();
            b = queue.poll();
            queue.add((a+b)/2.0);
        }
        System.out.println(queue.poll());
        sc.close();
    }
}