import java.util.*;
import java.io.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int N = Integer.parseInt(sc.next());
        List<Integer> list = new ArrayList<Integer>(N);
        for (int i = 0; i < N; i++) {
            list.add(new Integer(sc.next()));
        }
        sc.close();
        Collections.sort(list);

        double max = list.get(0);
        for (int i = 1; i < N; i++) {
            double temp = max;
            max = (temp + list.get(i)) / 2.0;
        }

        out.printf("%.10f\n", max);
        out.flush();
    }
} import java.util.*; util.* java import java.io.*; io.* java class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int N = Integer.parseInt(sc.next());
        List<Integer> list = new ArrayList<Integer>(N);
        for (int i = 0; i < N; i++) {
            list.add(new Integer(sc.next()));
        }
        sc.close();
        Collections.sort(list);

        double max = list.get(0);
        for (int i = 1; i < N; i++) {
            double temp = max;
            max = (temp + list.get(i)) / 2.0;
        }

        out.printf("%.10f\n", max);
        out.flush();
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int N = Integer.parseInt(sc.next());
        List<Integer> list = new ArrayList<Integer>(N);
        for (int i = 0; i < N; i++) {
            list.add(new Integer(sc.next()));
        }
        sc.close();
        Collections.sort(list);

        double max = list.get(0);
        for (int i = 1; i < N; i++) {
            double temp = max;
            max = (temp + list.get(i)) / 2.0;
        }

        out.printf("%.10f\n", max);
        out.flush();
    } main {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int N = Integer.parseInt(sc.next());
        List<Integer> list = new ArrayList<Integer>(N);
        for (int i = 0; i < N; i++) {
            list.add(new Integer(sc.next()));
        }
        sc.close();
        Collections.sort(list);

        double max = list.get(0);
        for (int i = 1; i < N; i++) {
            double temp = max;
            max = (temp + list.get(i)) / 2.0;
        }

        out.printf("%.10f\n", max);
        out.flush();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) int N = Integer.parseInt(sc.next()); N Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc List<Integer> list = new ArrayList<Integer>(N); list new ArrayList<Integer>(N) for (int i = 0; i < N; i++) {
            list.add(new Integer(sc.next()));
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            list.add(new Integer(sc.next()));
        } {
            list.add(new Integer(sc.next()));
        } list.add(new Integer(sc.next())) list.add list new Integer(sc.next()) sc.close() sc.close sc Collections.sort(list) Collections.sort Collections list double max = list.get(0); max list.get(0) list.get list 0 for (int i = 1; i < N; i++) {
            double temp = max;
            max = (temp + list.get(i)) / 2.0;
        } int i = 1; int i = 1; i 1 i < N i N i++ i++ i {
            double temp = max;
            max = (temp + list.get(i)) / 2.0;
        } {
            double temp = max;
            max = (temp + list.get(i)) / 2.0;
        } double temp = max; temp max max = (temp + list.get(i)) / 2.0 max (temp + list.get(i)) / 2.0 (temp + list.get(i)) temp list.get(i) list.get list i 2.0 out.printf("%.10f\n", max) out.printf out "%.10f\n" max out.flush() out.flush out String[] args args
import java.util.*;
import java.io.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int N = Integer.parseInt(sc.next());
        List<Integer> list = new ArrayList<Integer>(N);
        for (int i = 0; i < N; i++) {
            list.add(new Integer(sc.next()));
        }
        sc.close();
        Collections.sort(list);

        double max = list.get(0);
        for (int i = 1; i < N; i++) {
            double temp = max;
            max = (temp + list.get(i)) / 2.0;
        }

        out.printf("%.10f\n", max);
        out.flush();
    }
}
