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

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<Double> list = new ArrayList<Double>();

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

		Collections.sort(list);

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

		System.out.println(list.get(n - 1));
	}
} 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) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<Double> list = new ArrayList<Double>();

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

		Collections.sort(list);

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

		System.out.println(list.get(n - 1));
	}
} Main public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<Double> list = new ArrayList<Double>();

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

		Collections.sort(list);

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

		System.out.println(list.get(n - 1));
	} main {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<Double> list = new ArrayList<Double>();

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

		Collections.sort(list);

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

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

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

		Collections.sort(list);

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

		System.out.println(list.get(n - 1));
	}
} public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<Double> list = new ArrayList<Double>();

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

		Collections.sort(list);

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

		System.out.println(list.get(n - 1));
	}
} Main
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<Double> list = new ArrayList<Double>();

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

		Collections.sort(list);

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

		System.out.println(list.get(n - 1));
	}
}