import java.util.*;

public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        double[] v = new double[n];

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

        for(int i = 0;i<n;i++){
            v[i] = Double.parseDouble(sc.next());
        }
        Arrays.sort(v);
        double ans = 0;
        ans = (v[0] + v[1]) / 2.0;
        for(int i = 1;i <n - 1;i++){
            ans = (ans + v[i + 1]) / 2.0;
        }
        System.out.println(ans);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        double[] v = new double[n];

        for(int i = 0;i<n;i++){
            v[i] = Double.parseDouble(sc.next());
        }
        Arrays.sort(v);
        double ans = 0;
        ans = (v[0] + v[1]) / 2.0;
        for(int i = 1;i <n - 1;i++){
            ans = (ans + v[i + 1]) / 2.0;
        }
        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        double[] v = new double[n];

        for(int i = 0;i<n;i++){
            v[i] = Double.parseDouble(sc.next());
        }
        Arrays.sort(v);
        double ans = 0;
        ans = (v[0] + v[1]) / 2.0;
        for(int i = 1;i <n - 1;i++){
            ans = (ans + v[i + 1]) / 2.0;
        }
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = Integer.parseInt(sc.next()); n Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc double[] v = new double[n]; v new double[n] n for(int i = 0;i<n;i++){
            v[i] = Double.parseDouble(sc.next());
        } int i = 0; int i = 0; i 0 i<n i n i++ i++ i {
            v[i] = Double.parseDouble(sc.next());
        } {
            v[i] = Double.parseDouble(sc.next());
        } v[i] = Double.parseDouble(sc.next()) v[i] v i Double.parseDouble(sc.next()) Double.parseDouble Double sc.next() sc.next sc Arrays.sort(v) Arrays.sort Arrays v double ans = 0; ans 0 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 = 1;i <n - 1;i++){
            ans = (ans + v[i + 1]) / 2.0;
        } int i = 1; int i = 1; i 1 i <n - 1 i n - 1 n 1 i++ i++ i {
            ans = (ans + v[i + 1]) / 2.0;
        } {
            ans = (ans + v[i + 1]) / 2.0;
        } ans = (ans + v[i + 1]) / 2.0 ans (ans + v[i + 1]) / 2.0 (ans + v[i + 1]) ans v[i + 1] v i + 1 i 1 2.0 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        double[] v = new double[n];

        for(int i = 0;i<n;i++){
            v[i] = Double.parseDouble(sc.next());
        }
        Arrays.sort(v);
        double ans = 0;
        ans = (v[0] + v[1]) / 2.0;
        for(int i = 1;i <n - 1;i++){
            ans = (ans + v[i + 1]) / 2.0;
        }
        System.out.println(ans);
    }
} public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        double[] v = new double[n];

        for(int i = 0;i<n;i++){
            v[i] = Double.parseDouble(sc.next());
        }
        Arrays.sort(v);
        double ans = 0;
        ans = (v[0] + v[1]) / 2.0;
        for(int i = 1;i <n - 1;i++){
            ans = (ans + v[i + 1]) / 2.0;
        }
        System.out.println(ans);
    }
} Main
import java.util.*;

public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        double[] v = new double[n];

        for(int i = 0;i<n;i++){
            v[i] = Double.parseDouble(sc.next());
        }
        Arrays.sort(v);
        double ans = 0;
        ans = (v[0] + v[1]) / 2.0;
        for(int i = 1;i <n - 1;i++){
            ans = (ans + v[i + 1]) / 2.0;
        }
        System.out.println(ans);
    }
}