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

class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] v = new int[n + 1];
		for (int i = 1; i < n + 1; i++)
			v[i] = sc.nextInt();
		sc.close();

		Arrays.sort(v);
		double ans = v[1];

		for (int i = 2; i < n + 1; i++)
			ans = (ans + v[i]) / 2;

		System.out.print(ans);

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

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] v = new int[n + 1];
		for (int i = 1; i < n + 1; i++)
			v[i] = sc.nextInt();
		sc.close();

		Arrays.sort(v);
		double ans = v[1];

		for (int i = 2; i < n + 1; i++)
			ans = (ans + v[i]) / 2;

		System.out.print(ans);

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

		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] v = new int[n + 1];
		for (int i = 1; i < n + 1; i++)
			v[i] = sc.nextInt();
		sc.close();

		Arrays.sort(v);
		double ans = v[1];

		for (int i = 2; i < n + 1; i++)
			ans = (ans + v[i]) / 2;

		System.out.print(ans);

	} main {

		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] v = new int[n + 1];
		for (int i = 1; i < n + 1; i++)
			v[i] = sc.nextInt();
		sc.close();

		Arrays.sort(v);
		double ans = v[1];

		for (int i = 2; i < n + 1; i++)
			ans = (ans + v[i]) / 2;

		System.out.print(ans);

	} 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 + 1]; v new int[n + 1] n + 1 n 1 for (int i = 1; i < n + 1; i++)
			v[i] = sc.nextInt(); int i = 1; int i = 1; i 1 i < n + 1 i n + 1 n 1 i++ i++ i v[i] = sc.nextInt(); v[i] = sc.nextInt() v[i] v i sc.nextInt() sc.nextInt sc sc.close() sc.close sc Arrays.sort(v) Arrays.sort Arrays v double ans = v[1]; ans v[1] v 1 for (int i = 2; i < n + 1; i++)
			ans = (ans + v[i]) / 2; int i = 2; int i = 2; i 2 i < n + 1 i n + 1 n 1 i++ i++ i ans = (ans + v[i]) / 2; ans = (ans + v[i]) / 2 ans (ans + v[i]) / 2 (ans + v[i]) ans v[i] v i 2 System.out.print(ans) System.out.print System.out System System.out ans String[] args args
import java.util.Arrays;
import java.util.Scanner;

class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] v = new int[n + 1];
		for (int i = 1; i < n + 1; i++)
			v[i] = sc.nextInt();
		sc.close();

		Arrays.sort(v);
		double ans = v[1];

		for (int i = 2; i < n + 1; i++)
			ans = (ans + v[i]) / 2;

		System.out.print(ans);

	}
}