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

class Main {

    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        
        int n = sc.nextInt();

        double[] v = new double[n];
        for(int i=0;i<n;i++){
            v[i] = sc.nextInt();
        }

        Arrays.sort(v);

        for(int i=0;i<n-1;i++){
            v[i+1]=(double) ((v[i]+v[i+1])/2);
        }

        System.out.println(v[n-1]);

    }

    static class MyScanner {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15);
        StringTokenizer tokenizer;
    
        String next() {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            }
            return tokenizer.nextToken();
        }
    
        int nextInt() {
            return Integer.parseInt(next());
        }
    
        long nextLong() {
            return Long.parseLong(next());
        }
    }
} import java.io.*; io.* java import java.util.*; util.* java class Main {

    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        
        int n = sc.nextInt();

        double[] v = new double[n];
        for(int i=0;i<n;i++){
            v[i] = sc.nextInt();
        }

        Arrays.sort(v);

        for(int i=0;i<n-1;i++){
            v[i+1]=(double) ((v[i]+v[i+1])/2);
        }

        System.out.println(v[n-1]);

    }

    static class MyScanner {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15);
        StringTokenizer tokenizer;
    
        String next() {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            }
            return tokenizer.nextToken();
        }
    
        int nextInt() {
            return Integer.parseInt(next());
        }
    
        long nextLong() {
            return Long.parseLong(next());
        }
    }
} Main public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        
        int n = sc.nextInt();

        double[] v = new double[n];
        for(int i=0;i<n;i++){
            v[i] = sc.nextInt();
        }

        Arrays.sort(v);

        for(int i=0;i<n-1;i++){
            v[i+1]=(double) ((v[i]+v[i+1])/2);
        }

        System.out.println(v[n-1]);

    } main {
        MyScanner sc = new MyScanner();
        
        int n = sc.nextInt();

        double[] v = new double[n];
        for(int i=0;i<n;i++){
            v[i] = sc.nextInt();
        }

        Arrays.sort(v);

        for(int i=0;i<n-1;i++){
            v[i+1]=(double) ((v[i]+v[i+1])/2);
        }

        System.out.println(v[n-1]);

    } MyScanner sc = new MyScanner(); sc new MyScanner() int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc double[] v = new double[n]; v new double[n] n for(int i=0;i<n;i++){
            v[i] = sc.nextInt();
        } int i=0; int i=0; i 0 i<n i n i++ i++ i {
            v[i] = sc.nextInt();
        } {
            v[i] = sc.nextInt();
        } v[i] = sc.nextInt() v[i] v i sc.nextInt() sc.nextInt sc Arrays.sort(v) Arrays.sort Arrays v for(int i=0;i<n-1;i++){
            v[i+1]=(double) ((v[i]+v[i+1])/2);
        } int i=0; int i=0; i 0 i<n-1 i n-1 n 1 i++ i++ i {
            v[i+1]=(double) ((v[i]+v[i+1])/2);
        } {
            v[i+1]=(double) ((v[i]+v[i+1])/2);
        } v[i+1]=(double) ((v[i]+v[i+1])/2) v[i+1] v i+1 i 1 (double) ((v[i]+v[i+1])/2) (v[i]+v[i+1]) v[i] v i v[i+1] v i+1 i 1 2 System.out.println(v[n-1]) System.out.println System.out System System.out v[n-1] v n-1 n 1 String[] args args static class MyScanner {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15);
        StringTokenizer tokenizer;
    
        String next() {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            }
            return tokenizer.nextToken();
        }
    
        int nextInt() {
            return Integer.parseInt(next());
        }
    
        long nextLong() {
            return Long.parseLong(next());
        }
    } MyScanner BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15); reader new BufferedReader(new InputStreamReader(System.in), 1 << 15) StringTokenizer tokenizer; tokenizer String next() {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            }
            return tokenizer.nextToken();
        } next {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            }
            return tokenizer.nextToken();
        } try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            } catch (IOException ignored) {
            } IOException ignored {
            } {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
                    tokenizer = new StringTokenizer(reader.readLine());
                } tokenizer = new StringTokenizer(reader.readLine()) tokenizer new StringTokenizer(reader.readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer int nextInt() {
            return Integer.parseInt(next());
        } nextInt {
            return Integer.parseInt(next());
        } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() {
            return Long.parseLong(next());
        } nextLong {
            return Long.parseLong(next());
        } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next
import java.io.*;
import java.util.*;

class Main {

    public static void main(String[] args) {
        MyScanner sc = new MyScanner();
        
        int n = sc.nextInt();

        double[] v = new double[n];
        for(int i=0;i<n;i++){
            v[i] = sc.nextInt();
        }

        Arrays.sort(v);

        for(int i=0;i<n-1;i++){
            v[i+1]=(double) ((v[i]+v[i+1])/2);
        }

        System.out.println(v[n-1]);

    }

    static class MyScanner {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in), 1 << 15);
        StringTokenizer tokenizer;
    
        String next() {
            try {
                while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                    tokenizer = new StringTokenizer(reader.readLine());
                }
            } catch (IOException ignored) {
            }
            return tokenizer.nextToken();
        }
    
        int nextInt() {
            return Integer.parseInt(next());
        }
    
        long nextLong() {
            return Long.parseLong(next());
        }
    }
}