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

public class Main {
    public static void main(String[] args) {
        try (Scanner in = new Scanner(System.in)) {
            int N = in.nextInt();
            int[] v = new int[N];
            for (int i = 0; i < N; i++) {
                v[i] = in.nextInt();
            }

            PriorityQueue<Double> pq = new PriorityQueue<Double>();
            for (int i = 0; i < N; i++) {
                pq.add((double) v[i]);
            }
            for (; pq.size() > 1;) {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            }

            System.out.println(pq.poll());
        }
    }
} import java.util.PriorityQueue; PriorityQueue java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        try (Scanner in = new Scanner(System.in)) {
            int N = in.nextInt();
            int[] v = new int[N];
            for (int i = 0; i < N; i++) {
                v[i] = in.nextInt();
            }

            PriorityQueue<Double> pq = new PriorityQueue<Double>();
            for (int i = 0; i < N; i++) {
                pq.add((double) v[i]);
            }
            for (; pq.size() > 1;) {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            }

            System.out.println(pq.poll());
        }
    }
} Main public static void main(String[] args) {
        try (Scanner in = new Scanner(System.in)) {
            int N = in.nextInt();
            int[] v = new int[N];
            for (int i = 0; i < N; i++) {
                v[i] = in.nextInt();
            }

            PriorityQueue<Double> pq = new PriorityQueue<Double>();
            for (int i = 0; i < N; i++) {
                pq.add((double) v[i]);
            }
            for (; pq.size() > 1;) {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            }

            System.out.println(pq.poll());
        }
    } main {
        try (Scanner in = new Scanner(System.in)) {
            int N = in.nextInt();
            int[] v = new int[N];
            for (int i = 0; i < N; i++) {
                v[i] = in.nextInt();
            }

            PriorityQueue<Double> pq = new PriorityQueue<Double>();
            for (int i = 0; i < N; i++) {
                pq.add((double) v[i]);
            }
            for (; pq.size() > 1;) {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            }

            System.out.println(pq.poll());
        }
    } try (Scanner in = new Scanner(System.in)) {
            int N = in.nextInt();
            int[] v = new int[N];
            for (int i = 0; i < N; i++) {
                v[i] = in.nextInt();
            }

            PriorityQueue<Double> pq = new PriorityQueue<Double>();
            for (int i = 0; i < N; i++) {
                pq.add((double) v[i]);
            }
            for (; pq.size() > 1;) {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            }

            System.out.println(pq.poll());
        } {
            int N = in.nextInt();
            int[] v = new int[N];
            for (int i = 0; i < N; i++) {
                v[i] = in.nextInt();
            }

            PriorityQueue<Double> pq = new PriorityQueue<Double>();
            for (int i = 0; i < N; i++) {
                pq.add((double) v[i]);
            }
            for (; pq.size() > 1;) {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            }

            System.out.println(pq.poll());
        } Scanner in = new Scanner(System.in) Scanner in = new Scanner(System.in) new Scanner(System.in) int N = in.nextInt(); N in.nextInt() in.nextInt in int[] v = new int[N]; v new int[N] N for (int i = 0; i < N; i++) {
                v[i] = in.nextInt();
            } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
                v[i] = in.nextInt();
            } {
                v[i] = in.nextInt();
            } v[i] = in.nextInt() v[i] v i in.nextInt() in.nextInt in PriorityQueue<Double> pq = new PriorityQueue<Double>(); pq new PriorityQueue<Double>() for (int i = 0; i < N; i++) {
                pq.add((double) v[i]);
            } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
                pq.add((double) v[i]);
            } {
                pq.add((double) v[i]);
            } pq.add((double) v[i]) pq.add pq (double) v[i] v i for (; pq.size() > 1;) {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            } ; pq.size() > 1 pq.size() pq.size pq 1 {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            } {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            } double d = pq.poll(); d pq.poll() pq.poll pq double d2 = pq.poll(); d2 pq.poll() pq.poll pq pq.add((d + d2) / 2) pq.add pq (d + d2) / 2 (d + d2) d d2 2 System.out.println(pq.poll()) System.out.println System.out System System.out pq.poll() pq.poll pq String[] args args public class Main {
    public static void main(String[] args) {
        try (Scanner in = new Scanner(System.in)) {
            int N = in.nextInt();
            int[] v = new int[N];
            for (int i = 0; i < N; i++) {
                v[i] = in.nextInt();
            }

            PriorityQueue<Double> pq = new PriorityQueue<Double>();
            for (int i = 0; i < N; i++) {
                pq.add((double) v[i]);
            }
            for (; pq.size() > 1;) {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            }

            System.out.println(pq.poll());
        }
    }
} public class Main {
    public static void main(String[] args) {
        try (Scanner in = new Scanner(System.in)) {
            int N = in.nextInt();
            int[] v = new int[N];
            for (int i = 0; i < N; i++) {
                v[i] = in.nextInt();
            }

            PriorityQueue<Double> pq = new PriorityQueue<Double>();
            for (int i = 0; i < N; i++) {
                pq.add((double) v[i]);
            }
            for (; pq.size() > 1;) {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            }

            System.out.println(pq.poll());
        }
    }
} Main
import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        try (Scanner in = new Scanner(System.in)) {
            int N = in.nextInt();
            int[] v = new int[N];
            for (int i = 0; i < N; i++) {
                v[i] = in.nextInt();
            }

            PriorityQueue<Double> pq = new PriorityQueue<Double>();
            for (int i = 0; i < N; i++) {
                pq.add((double) v[i]);
            }
            for (; pq.size() > 1;) {
                double d = pq.poll();
                double d2 = pq.poll();
                pq.add((d + d2) / 2);
            }

            System.out.println(pq.poll());
        }
    }
}
