import java.util.Arrays;
import java.util.Scanner;

public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		int n = Integer.parseInt(scanner.nextLine());

		String[] temp = scanner.nextLine().split(" ");
		int[] list = new int[n];
		double ans = 0;
		for(int i = 0; i < n; i++) {

			list[i] = Integer.parseInt(temp[i]);
		}

		Arrays.sort(list);


		ans = (list[0] + list[1]) / 2.0;


		for(int i = 2; i < n; i++) {

			ans = (ans + list[i]) / 2;

		}



		System.out.println(ans);







	}



} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		int n = Integer.parseInt(scanner.nextLine());

		String[] temp = scanner.nextLine().split(" ");
		int[] list = new int[n];
		double ans = 0;
		for(int i = 0; i < n; i++) {

			list[i] = Integer.parseInt(temp[i]);
		}

		Arrays.sort(list);


		ans = (list[0] + list[1]) / 2.0;


		for(int i = 2; i < n; i++) {

			ans = (ans + list[i]) / 2;

		}



		System.out.println(ans);







	}



} Main public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		int n = Integer.parseInt(scanner.nextLine());

		String[] temp = scanner.nextLine().split(" ");
		int[] list = new int[n];
		double ans = 0;
		for(int i = 0; i < n; i++) {

			list[i] = Integer.parseInt(temp[i]);
		}

		Arrays.sort(list);


		ans = (list[0] + list[1]) / 2.0;


		for(int i = 2; i < n; i++) {

			ans = (ans + list[i]) / 2;

		}



		System.out.println(ans);







	} main {

		Scanner scanner = new Scanner(System.in);
		int n = Integer.parseInt(scanner.nextLine());

		String[] temp = scanner.nextLine().split(" ");
		int[] list = new int[n];
		double ans = 0;
		for(int i = 0; i < n; i++) {

			list[i] = Integer.parseInt(temp[i]);
		}

		Arrays.sort(list);


		ans = (list[0] + list[1]) / 2.0;


		for(int i = 2; i < n; i++) {

			ans = (ans + list[i]) / 2;

		}



		System.out.println(ans);







	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) int n = Integer.parseInt(scanner.nextLine()); n Integer.parseInt(scanner.nextLine()) Integer.parseInt Integer scanner.nextLine() scanner.nextLine scanner String[] temp = scanner.nextLine().split(" "); temp scanner.nextLine().split(" ") scanner.nextLine().split scanner.nextLine() scanner.nextLine scanner " " int[] list = new int[n]; list new int[n] n double ans = 0; ans 0 for(int i = 0; i < n; i++) {

			list[i] = Integer.parseInt(temp[i]);
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {

			list[i] = Integer.parseInt(temp[i]);
		} {

			list[i] = Integer.parseInt(temp[i]);
		} list[i] = Integer.parseInt(temp[i]) list[i] list i Integer.parseInt(temp[i]) Integer.parseInt Integer temp[i] temp i Arrays.sort(list) Arrays.sort Arrays list ans = (list[0] + list[1]) / 2.0 ans (list[0] + list[1]) / 2.0 (list[0] + list[1]) list[0] list 0 list[1] list 1 2.0 for(int i = 2; i < n; i++) {

			ans = (ans + list[i]) / 2;

		} int i = 2; int i = 2; i 2 i < n i n i++ i++ i {

			ans = (ans + list[i]) / 2;

		} {

			ans = (ans + list[i]) / 2;

		} ans = (ans + list[i]) / 2 ans (ans + list[i]) / 2 (ans + list[i]) ans list[i] list i 2 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 scanner = new Scanner(System.in);
		int n = Integer.parseInt(scanner.nextLine());

		String[] temp = scanner.nextLine().split(" ");
		int[] list = new int[n];
		double ans = 0;
		for(int i = 0; i < n; i++) {

			list[i] = Integer.parseInt(temp[i]);
		}

		Arrays.sort(list);


		ans = (list[0] + list[1]) / 2.0;


		for(int i = 2; i < n; i++) {

			ans = (ans + list[i]) / 2;

		}



		System.out.println(ans);







	}



} public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		int n = Integer.parseInt(scanner.nextLine());

		String[] temp = scanner.nextLine().split(" ");
		int[] list = new int[n];
		double ans = 0;
		for(int i = 0; i < n; i++) {

			list[i] = Integer.parseInt(temp[i]);
		}

		Arrays.sort(list);


		ans = (list[0] + list[1]) / 2.0;


		for(int i = 2; i < n; i++) {

			ans = (ans + list[i]) / 2;

		}



		System.out.println(ans);







	}



} Main
import java.util.Arrays;
import java.util.Scanner;

public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		int n = Integer.parseInt(scanner.nextLine());

		String[] temp = scanner.nextLine().split(" ");
		int[] list = new int[n];
		double ans = 0;
		for(int i = 0; i < n; i++) {

			list[i] = Integer.parseInt(temp[i]);
		}

		Arrays.sort(list);


		ans = (list[0] + list[1]) / 2.0;


		for(int i = 2; i < n; i++) {

			ans = (ans + list[i]) / 2;

		}



		System.out.println(ans);







	}



}