import java.util.*;

public class Main {
    public static void main(String args[]) throws Exception {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        PriorityQueue<Double> pq = new PriorityQueue<>();
        for(int i = 0; i < n; i++)
        	pq.offer(sc.nextDouble());


        while(pq.size() > 1) {
        	double a = pq.poll();
        	double b = pq.poll();
        	pq.offer((a + b) / 2.0);
        }
        System.out.println(pq.peek());
    }
} import java.util.*; util.* java public class Main {
    public static void main(String args[]) throws Exception {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        PriorityQueue<Double> pq = new PriorityQueue<>();
        for(int i = 0; i < n; i++)
        	pq.offer(sc.nextDouble());


        while(pq.size() > 1) {
        	double a = pq.poll();
        	double b = pq.poll();
        	pq.offer((a + b) / 2.0);
        }
        System.out.println(pq.peek());
    }
} Main public static void main(String args[]) throws Exception {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        PriorityQueue<Double> pq = new PriorityQueue<>();
        for(int i = 0; i < n; i++)
        	pq.offer(sc.nextDouble());


        while(pq.size() > 1) {
        	double a = pq.poll();
        	double b = pq.poll();
        	pq.offer((a + b) / 2.0);
        }
        System.out.println(pq.peek());
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        PriorityQueue<Double> pq = new PriorityQueue<>();
        for(int i = 0; i < n; i++)
        	pq.offer(sc.nextDouble());


        while(pq.size() > 1) {
        	double a = pq.poll();
        	double b = pq.poll();
        	pq.offer((a + b) / 2.0);
        }
        System.out.println(pq.peek());
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc PriorityQueue<Double> pq = new PriorityQueue<>(); pq new PriorityQueue<>() for(int i = 0; i < n; i++)
        	pq.offer(sc.nextDouble()); int i = 0; int i = 0; i 0 i < n i n i++ i++ i pq.offer(sc.nextDouble()); pq.offer(sc.nextDouble()) pq.offer pq sc.nextDouble() sc.nextDouble sc while(pq.size() > 1) {
        	double a = pq.poll();
        	double b = pq.poll();
        	pq.offer((a + b) / 2.0);
        } pq.size() > 1 pq.size() pq.size pq 1 {
        	double a = pq.poll();
        	double b = pq.poll();
        	pq.offer((a + b) / 2.0);
        } double a = pq.poll(); a pq.poll() pq.poll pq double b = pq.poll(); b pq.poll() pq.poll pq pq.offer((a + b) / 2.0) pq.offer pq (a + b) / 2.0 (a + b) a b 2.0 System.out.println(pq.peek()) System.out.println System.out System System.out pq.peek() pq.peek pq String args[] args public class Main {
    public static void main(String args[]) throws Exception {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        PriorityQueue<Double> pq = new PriorityQueue<>();
        for(int i = 0; i < n; i++)
        	pq.offer(sc.nextDouble());


        while(pq.size() > 1) {
        	double a = pq.poll();
        	double b = pq.poll();
        	pq.offer((a + b) / 2.0);
        }
        System.out.println(pq.peek());
    }
} public class Main {
    public static void main(String args[]) throws Exception {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        PriorityQueue<Double> pq = new PriorityQueue<>();
        for(int i = 0; i < n; i++)
        	pq.offer(sc.nextDouble());


        while(pq.size() > 1) {
        	double a = pq.poll();
        	double b = pq.poll();
        	pq.offer((a + b) / 2.0);
        }
        System.out.println(pq.peek());
    }
} Main
import java.util.*;

public class Main {
    public static void main(String args[]) throws Exception {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        PriorityQueue<Double> pq = new PriorityQueue<>();
        for(int i = 0; i < n; i++)
        	pq.offer(sc.nextDouble());


        while(pq.size() > 1) {
        	double a = pq.poll();
        	double b = pq.poll();
        	pq.offer((a + b) / 2.0);
        }
        System.out.println(pq.peek());
    }
}
