import java.io.*;
import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        
        final int N = Integer.parseInt(sc.next());
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
            v[i] = Integer.parseInt(sc.next());
        }
        
        Arrays.sort(v);
        double ans = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
            ans = (ans + v[i]) / 2.0;
        }
        
        out.println(ans);
        
        out.flush();
    }
} import java.io.*; io.* java import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        
        final int N = Integer.parseInt(sc.next());
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
            v[i] = Integer.parseInt(sc.next());
        }
        
        Arrays.sort(v);
        double ans = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
            ans = (ans + v[i]) / 2.0;
        }
        
        out.println(ans);
        
        out.flush();
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        
        final int N = Integer.parseInt(sc.next());
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
            v[i] = Integer.parseInt(sc.next());
        }
        
        Arrays.sort(v);
        double ans = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
            ans = (ans + v[i]) / 2.0;
        }
        
        out.println(ans);
        
        out.flush();
    } main {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        
        final int N = Integer.parseInt(sc.next());
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
            v[i] = Integer.parseInt(sc.next());
        }
        
        Arrays.sort(v);
        double ans = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
            ans = (ans + v[i]) / 2.0;
        }
        
        out.println(ans);
        
        out.flush();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) final int N = Integer.parseInt(sc.next()); N Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int[] v = new int[N]; v new int[N] N for (int i = 0; i < N; i++) {
            v[i] = Integer.parseInt(sc.next());
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            v[i] = Integer.parseInt(sc.next());
        } {
            v[i] = Integer.parseInt(sc.next());
        } v[i] = Integer.parseInt(sc.next()) v[i] v i Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc Arrays.sort(v) Arrays.sort Arrays v double ans = (v[0] + v[1]) / 2.0; ans (v[0] + v[1]) / 2.0 (v[0] + v[1]) v[0] v 0 v[1] v 1 2.0 for (int i = 2; i < N; i++) {
            ans = (ans + v[i]) / 2.0;
        } int i = 2; int i = 2; i 2 i < N i N i++ i++ i {
            ans = (ans + v[i]) / 2.0;
        } {
            ans = (ans + v[i]) / 2.0;
        } ans = (ans + v[i]) / 2.0 ans (ans + v[i]) / 2.0 (ans + v[i]) ans v[i] v i 2.0 out.println(ans) out.println out ans out.flush() out.flush out String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        
        final int N = Integer.parseInt(sc.next());
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
            v[i] = Integer.parseInt(sc.next());
        }
        
        Arrays.sort(v);
        double ans = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
            ans = (ans + v[i]) / 2.0;
        }
        
        out.println(ans);
        
        out.flush();
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        
        final int N = Integer.parseInt(sc.next());
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
            v[i] = Integer.parseInt(sc.next());
        }
        
        Arrays.sort(v);
        double ans = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
            ans = (ans + v[i]) / 2.0;
        }
        
        out.println(ans);
        
        out.flush();
    }
} Main
import java.io.*;
import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);
        
        final int N = Integer.parseInt(sc.next());
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
            v[i] = Integer.parseInt(sc.next());
        }
        
        Arrays.sort(v);
        double ans = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
            ans = (ans + v[i]) / 2.0;
        }
        
        out.println(ans);
        
        out.flush();
    }
}