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

public class Main {
	public static void main(String arg[]) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double v[] = new double[n];

		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double s = (v[0] + v[1]) / 2;

		if (n >= 3) {
			for (int i = 2; i < n; i++) {

				s = (s + v[i]) / 2;

			}
		}
		System.out.println(s);

	}
} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String arg[]) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double v[] = new double[n];

		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double s = (v[0] + v[1]) / 2;

		if (n >= 3) {
			for (int i = 2; i < n; i++) {

				s = (s + v[i]) / 2;

			}
		}
		System.out.println(s);

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

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double v[] = new double[n];

		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double s = (v[0] + v[1]) / 2;

		if (n >= 3) {
			for (int i = 2; i < n; i++) {

				s = (s + v[i]) / 2;

			}
		}
		System.out.println(s);

	} main {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double v[] = new double[n];

		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double s = (v[0] + v[1]) / 2;

		if (n >= 3) {
			for (int i = 2; i < n; i++) {

				s = (s + v[i]) / 2;

			}
		}
		System.out.println(s);

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) 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.nextDouble();
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			v[i] = sc.nextDouble();
		} {
			v[i] = sc.nextDouble();
		} v[i] = sc.nextDouble() v[i] v i sc.nextDouble() sc.nextDouble sc sc.close() sc.close sc Arrays.sort(v) Arrays.sort Arrays v double s = (v[0] + v[1]) / 2; s (v[0] + v[1]) / 2 (v[0] + v[1]) v[0] v 0 v[1] v 1 2 if (n >= 3) {
			for (int i = 2; i < n; i++) {

				s = (s + v[i]) / 2;

			}
		} n >= 3 n 3 {
			for (int i = 2; i < n; i++) {

				s = (s + v[i]) / 2;

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

				s = (s + v[i]) / 2;

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

				s = (s + v[i]) / 2;

			} {

				s = (s + v[i]) / 2;

			} s = (s + v[i]) / 2 s (s + v[i]) / 2 (s + v[i]) s v[i] v i 2 System.out.println(s) System.out.println System.out System System.out s String arg[] arg public class Main {
	public static void main(String arg[]) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double v[] = new double[n];

		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double s = (v[0] + v[1]) / 2;

		if (n >= 3) {
			for (int i = 2; i < n; i++) {

				s = (s + v[i]) / 2;

			}
		}
		System.out.println(s);

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

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double v[] = new double[n];

		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double s = (v[0] + v[1]) / 2;

		if (n >= 3) {
			for (int i = 2; i < n; i++) {

				s = (s + v[i]) / 2;

			}
		}
		System.out.println(s);

	}
} Main

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

public class Main {
	public static void main(String arg[]) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double v[] = new double[n];

		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double s = (v[0] + v[1]) / 2;

		if (n >= 3) {
			for (int i = 2; i < n; i++) {

				s = (s + v[i]) / 2;

			}
		}
		System.out.println(s);

	}
}