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

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double[] v = new double[n];
		double ans = 0;

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

		Arrays.sort(v);

		ans = (v[0] + v[1])/2;
		for(int i = 2; i < n; i++) {
			ans = (ans + v[i])/2;
		}

		System.out.println(String.format("%.5f", 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 sc = new Scanner(System.in);

		int n = sc.nextInt();
		double[] v = new double[n];
		double ans = 0;

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

		Arrays.sort(v);

		ans = (v[0] + v[1])/2;
		for(int i = 2; i < n; i++) {
			ans = (ans + v[i])/2;
		}

		System.out.println(String.format("%.5f", ans));

	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double[] v = new double[n];
		double ans = 0;

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

		Arrays.sort(v);

		ans = (v[0] + v[1])/2;
		for(int i = 2; i < n; i++) {
			ans = (ans + v[i])/2;
		}

		System.out.println(String.format("%.5f", ans));

	} main {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double[] v = new double[n];
		double ans = 0;

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

		Arrays.sort(v);

		ans = (v[0] + v[1])/2;
		for(int i = 2; i < n; i++) {
			ans = (ans + v[i])/2;
		}

		System.out.println(String.format("%.5f", ans));

	} 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 double ans = 0; ans 0 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 Arrays.sort(v) Arrays.sort Arrays v ans = (v[0] + v[1])/2 ans (v[0] + v[1])/2 (v[0] + v[1]) v[0] v 0 v[1] v 1 2 for(int i = 2; i < n; i++) {
			ans = (ans + v[i])/2;
		} int i = 2; int i = 2; i 2 i < n i n i++ i++ i {
			ans = (ans + v[i])/2;
		} {
			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.println(String.format("%.5f", ans)) System.out.println System.out System System.out String.format("%.5f", ans) String.format String "%.5f" ans String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double[] v = new double[n];
		double ans = 0;

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

		Arrays.sort(v);

		ans = (v[0] + v[1])/2;
		for(int i = 2; i < n; i++) {
			ans = (ans + v[i])/2;
		}

		System.out.println(String.format("%.5f", ans));

	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double[] v = new double[n];
		double ans = 0;

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

		Arrays.sort(v);

		ans = (v[0] + v[1])/2;
		for(int i = 2; i < n; i++) {
			ans = (ans + v[i])/2;
		}

		System.out.println(String.format("%.5f", ans));

	}

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

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		double[] v = new double[n];
		double ans = 0;

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

		Arrays.sort(v);

		ans = (v[0] + v[1])/2;
		for(int i = 2; i < n; i++) {
			ans = (ans + v[i])/2;
		}

		System.out.println(String.format("%.5f", ans));

	}

}