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

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int a = scan.nextInt();
		double[] s = new double[a];
		for (int i = 0; i < a; i++) {
			s[i] = scan.nextDouble();
		}
		Arrays.sort(s);
		for (int i = 0; i < a - 1; i++) {
			s[i + 1] = (s[i] + s[i + 1]) / 2;
		}
		System.out.println(s[a - 1]);
	}
} import java.util.Arrays; Arrays 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 a = scan.nextInt();
		double[] s = new double[a];
		for (int i = 0; i < a; i++) {
			s[i] = scan.nextDouble();
		}
		Arrays.sort(s);
		for (int i = 0; i < a - 1; i++) {
			s[i + 1] = (s[i] + s[i + 1]) / 2;
		}
		System.out.println(s[a - 1]);
	}
} Main public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int a = scan.nextInt();
		double[] s = new double[a];
		for (int i = 0; i < a; i++) {
			s[i] = scan.nextDouble();
		}
		Arrays.sort(s);
		for (int i = 0; i < a - 1; i++) {
			s[i + 1] = (s[i] + s[i + 1]) / 2;
		}
		System.out.println(s[a - 1]);
	} main {
		Scanner scan = new Scanner(System.in);
		int a = scan.nextInt();
		double[] s = new double[a];
		for (int i = 0; i < a; i++) {
			s[i] = scan.nextDouble();
		}
		Arrays.sort(s);
		for (int i = 0; i < a - 1; i++) {
			s[i + 1] = (s[i] + s[i + 1]) / 2;
		}
		System.out.println(s[a - 1]);
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int a = scan.nextInt(); a scan.nextInt() scan.nextInt scan double[] s = new double[a]; s new double[a] a for (int i = 0; i < a; i++) {
			s[i] = scan.nextDouble();
		} int i = 0; int i = 0; i 0 i < a i a i++ i++ i {
			s[i] = scan.nextDouble();
		} {
			s[i] = scan.nextDouble();
		} s[i] = scan.nextDouble() s[i] s i scan.nextDouble() scan.nextDouble scan Arrays.sort(s) Arrays.sort Arrays s for (int i = 0; i < a - 1; i++) {
			s[i + 1] = (s[i] + s[i + 1]) / 2;
		} int i = 0; int i = 0; i 0 i < a - 1 i a - 1 a 1 i++ i++ i {
			s[i + 1] = (s[i] + s[i + 1]) / 2;
		} {
			s[i + 1] = (s[i] + s[i + 1]) / 2;
		} s[i + 1] = (s[i] + s[i + 1]) / 2 s[i + 1] s i + 1 i 1 (s[i] + s[i + 1]) / 2 (s[i] + s[i + 1]) s[i] s i s[i + 1] s i + 1 i 1 2 System.out.println(s[a - 1]) System.out.println System.out System System.out s[a - 1] s a - 1 a 1 String[] args args public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int a = scan.nextInt();
		double[] s = new double[a];
		for (int i = 0; i < a; i++) {
			s[i] = scan.nextDouble();
		}
		Arrays.sort(s);
		for (int i = 0; i < a - 1; i++) {
			s[i + 1] = (s[i] + s[i + 1]) / 2;
		}
		System.out.println(s[a - 1]);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int a = scan.nextInt();
		double[] s = new double[a];
		for (int i = 0; i < a; i++) {
			s[i] = scan.nextDouble();
		}
		Arrays.sort(s);
		for (int i = 0; i < a - 1; i++) {
			s[i + 1] = (s[i] + s[i + 1]) / 2;
		}
		System.out.println(s[a - 1]);
	}
} Main
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int a = scan.nextInt();
		double[] s = new double[a];
		for (int i = 0; i < a; i++) {
			s[i] = scan.nextDouble();
		}
		Arrays.sort(s);
		for (int i = 0; i < a - 1; i++) {
			s[i + 1] = (s[i] + s[i + 1]) / 2;
		}
		System.out.println(s[a - 1]);
	}
}
