
import java.util.*;
import java.lang.*;

class Main {
	public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int v[] = new int[N];
        for(int i = 0; i < N; i++){
            v[i] = sc.nextInt();
        }
        double vMax = 0;
        Arrays.sort(v);
        vMax += (double)v[0] / Math.pow(2, N-1);
        for(int i = 1; i < N; i++){
            vMax += (double)v[i] / Math.pow(2, N-i);
        }


        System.out.println(vMax);




    }
}


 import java.util.*; util.* java import java.lang.*; lang.* java class Main {
	public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int v[] = new int[N];
        for(int i = 0; i < N; i++){
            v[i] = sc.nextInt();
        }
        double vMax = 0;
        Arrays.sort(v);
        vMax += (double)v[0] / Math.pow(2, N-1);
        for(int i = 1; i < N; i++){
            vMax += (double)v[i] / Math.pow(2, N-i);
        }


        System.out.println(vMax);




    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int v[] = new int[N];
        for(int i = 0; i < N; i++){
            v[i] = sc.nextInt();
        }
        double vMax = 0;
        Arrays.sort(v);
        vMax += (double)v[0] / Math.pow(2, N-1);
        for(int i = 1; i < N; i++){
            vMax += (double)v[i] / Math.pow(2, N-i);
        }


        System.out.println(vMax);




    } main {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int v[] = new int[N];
        for(int i = 0; i < N; i++){
            v[i] = sc.nextInt();
        }
        double vMax = 0;
        Arrays.sort(v);
        vMax += (double)v[0] / Math.pow(2, N-1);
        for(int i = 1; i < N; i++){
            vMax += (double)v[i] / Math.pow(2, N-i);
        }


        System.out.println(vMax);




    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int v[] = new int[N]; v new int[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 double vMax = 0; vMax 0 Arrays.sort(v) Arrays.sort Arrays v vMax += (double)v[0] / Math.pow(2, N-1) vMax (double)v[0] / Math.pow(2, N-1) (double)v[0] v 0 Math.pow(2, N-1) Math.pow Math 2 N-1 N 1 for(int i = 1; i < N; i++){
            vMax += (double)v[i] / Math.pow(2, N-i);
        } int i = 1; int i = 1; i 1 i < N i N i++ i++ i {
            vMax += (double)v[i] / Math.pow(2, N-i);
        } {
            vMax += (double)v[i] / Math.pow(2, N-i);
        } vMax += (double)v[i] / Math.pow(2, N-i) vMax (double)v[i] / Math.pow(2, N-i) (double)v[i] v i Math.pow(2, N-i) Math.pow Math 2 N-i N i System.out.println(vMax) System.out.println System.out System System.out vMax String[] args args

import java.util.*;
import java.lang.*;

class Main {
	public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int v[] = new int[N];
        for(int i = 0; i < N; i++){
            v[i] = sc.nextInt();
        }
        double vMax = 0;
        Arrays.sort(v);
        vMax += (double)v[0] / Math.pow(2, N-1);
        for(int i = 1; i < N; i++){
            vMax += (double)v[i] / Math.pow(2, N-i);
        }


        System.out.println(vMax);




    }
}



