import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

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

		int n;

		double a;

		Scanner sc = new Scanner(System.in);

		n = sc.nextInt();

		ArrayList<Double> list = new ArrayList<>();

		for (int i = 0; i < n; i++) {
			list.add(sc.nextDouble());
		}

		Collections.sort(list);

		a = list.get(0);

		for (int i = 1; i < n; i++) {
			a = (a + list.get(i)) / 2;
		}

		System.out.println(a);


	}
} import java.util.ArrayList; ArrayList java.util import java.util.Collections; Collections java.util import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {

		int n;

		double a;

		Scanner sc = new Scanner(System.in);

		n = sc.nextInt();

		ArrayList<Double> list = new ArrayList<>();

		for (int i = 0; i < n; i++) {
			list.add(sc.nextDouble());
		}

		Collections.sort(list);

		a = list.get(0);

		for (int i = 1; i < n; i++) {
			a = (a + list.get(i)) / 2;
		}

		System.out.println(a);


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

		int n;

		double a;

		Scanner sc = new Scanner(System.in);

		n = sc.nextInt();

		ArrayList<Double> list = new ArrayList<>();

		for (int i = 0; i < n; i++) {
			list.add(sc.nextDouble());
		}

		Collections.sort(list);

		a = list.get(0);

		for (int i = 1; i < n; i++) {
			a = (a + list.get(i)) / 2;
		}

		System.out.println(a);


	} main {

		int n;

		double a;

		Scanner sc = new Scanner(System.in);

		n = sc.nextInt();

		ArrayList<Double> list = new ArrayList<>();

		for (int i = 0; i < n; i++) {
			list.add(sc.nextDouble());
		}

		Collections.sort(list);

		a = list.get(0);

		for (int i = 1; i < n; i++) {
			a = (a + list.get(i)) / 2;
		}

		System.out.println(a);


	} int n; n double a; a Scanner sc = new Scanner(System.in); sc new Scanner(System.in) n = sc.nextInt() n sc.nextInt() sc.nextInt sc ArrayList<Double> list = new ArrayList<>(); list new ArrayList<>() for (int i = 0; i < n; i++) {
			list.add(sc.nextDouble());
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			list.add(sc.nextDouble());
		} {
			list.add(sc.nextDouble());
		} list.add(sc.nextDouble()) list.add list sc.nextDouble() sc.nextDouble sc Collections.sort(list) Collections.sort Collections list a = list.get(0) a list.get(0) list.get list 0 for (int i = 1; i < n; i++) {
			a = (a + list.get(i)) / 2;
		} int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
			a = (a + list.get(i)) / 2;
		} {
			a = (a + list.get(i)) / 2;
		} a = (a + list.get(i)) / 2 a (a + list.get(i)) / 2 (a + list.get(i)) a list.get(i) list.get list i 2 System.out.println(a) System.out.println System.out System System.out a String[] args args public class Main {
	public static void main(String[] args) {

		int n;

		double a;

		Scanner sc = new Scanner(System.in);

		n = sc.nextInt();

		ArrayList<Double> list = new ArrayList<>();

		for (int i = 0; i < n; i++) {
			list.add(sc.nextDouble());
		}

		Collections.sort(list);

		a = list.get(0);

		for (int i = 1; i < n; i++) {
			a = (a + list.get(i)) / 2;
		}

		System.out.println(a);


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

		int n;

		double a;

		Scanner sc = new Scanner(System.in);

		n = sc.nextInt();

		ArrayList<Double> list = new ArrayList<>();

		for (int i = 0; i < n; i++) {
			list.add(sc.nextDouble());
		}

		Collections.sort(list);

		a = list.get(0);

		for (int i = 1; i < n; i++) {
			a = (a + list.get(i)) / 2;
		}

		System.out.println(a);


	}
} Main
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

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

		int n;

		double a;

		Scanner sc = new Scanner(System.in);

		n = sc.nextInt();

		ArrayList<Double> list = new ArrayList<>();

		for (int i = 0; i < n; i++) {
			list.add(sc.nextDouble());
		}

		Collections.sort(list);

		a = list.get(0);

		for (int i = 1; i < n; i++) {
			a = (a + list.get(i)) / 2;
		}

		System.out.println(a);


	}
}
