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

public class Main {

	static int n;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		n = Integer.parseInt(sc.next());
		int[] values = new int[n];
		for (int i = 0; i < n; i++) {
			values[i] = Integer.parseInt(sc.next());
		}
		Arrays.sort(values);

		double middle = values[0];
		for (int i = 1; i < n; i++) {
			middle = (middle + values[i]) / 2.0;
		}

		System.out.println(middle);

	}

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

	static int n;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		n = Integer.parseInt(sc.next());
		int[] values = new int[n];
		for (int i = 0; i < n; i++) {
			values[i] = Integer.parseInt(sc.next());
		}
		Arrays.sort(values);

		double middle = values[0];
		for (int i = 1; i < n; i++) {
			middle = (middle + values[i]) / 2.0;
		}

		System.out.println(middle);

	}

} Main static int n; n public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		n = Integer.parseInt(sc.next());
		int[] values = new int[n];
		for (int i = 0; i < n; i++) {
			values[i] = Integer.parseInt(sc.next());
		}
		Arrays.sort(values);

		double middle = values[0];
		for (int i = 1; i < n; i++) {
			middle = (middle + values[i]) / 2.0;
		}

		System.out.println(middle);

	} main {
		Scanner sc = new Scanner(System.in);
		n = Integer.parseInt(sc.next());
		int[] values = new int[n];
		for (int i = 0; i < n; i++) {
			values[i] = Integer.parseInt(sc.next());
		}
		Arrays.sort(values);

		double middle = values[0];
		for (int i = 1; i < n; i++) {
			middle = (middle + values[i]) / 2.0;
		}

		System.out.println(middle);

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) n = Integer.parseInt(sc.next()) n Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc int[] values = new int[n]; values new int[n] n for (int i = 0; i < n; i++) {
			values[i] = Integer.parseInt(sc.next());
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			values[i] = Integer.parseInt(sc.next());
		} {
			values[i] = Integer.parseInt(sc.next());
		} values[i] = Integer.parseInt(sc.next()) values[i] values i Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc Arrays.sort(values) Arrays.sort Arrays values double middle = values[0]; middle values[0] values 0 for (int i = 1; i < n; i++) {
			middle = (middle + values[i]) / 2.0;
		} int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
			middle = (middle + values[i]) / 2.0;
		} {
			middle = (middle + values[i]) / 2.0;
		} middle = (middle + values[i]) / 2.0 middle (middle + values[i]) / 2.0 (middle + values[i]) middle values[i] values i 2.0 System.out.println(middle) System.out.println System.out System System.out middle String[] args args public class Main {

	static int n;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		n = Integer.parseInt(sc.next());
		int[] values = new int[n];
		for (int i = 0; i < n; i++) {
			values[i] = Integer.parseInt(sc.next());
		}
		Arrays.sort(values);

		double middle = values[0];
		for (int i = 1; i < n; i++) {
			middle = (middle + values[i]) / 2.0;
		}

		System.out.println(middle);

	}

} public class Main {

	static int n;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		n = Integer.parseInt(sc.next());
		int[] values = new int[n];
		for (int i = 0; i < n; i++) {
			values[i] = Integer.parseInt(sc.next());
		}
		Arrays.sort(values);

		double middle = values[0];
		for (int i = 1; i < n; i++) {
			middle = (middle + values[i]) / 2.0;
		}

		System.out.println(middle);

	}

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

public class Main {

	static int n;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		n = Integer.parseInt(sc.next());
		int[] values = new int[n];
		for (int i = 0; i < n; i++) {
			values[i] = Integer.parseInt(sc.next());
		}
		Arrays.sort(values);

		double middle = values[0];
		for (int i = 1; i < n; i++) {
			middle = (middle + values[i]) / 2.0;
		}

		System.out.println(middle);

	}

}
