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

public class Main {

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

	}

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

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

	}

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

	} main {
		Scanner s = new Scanner(System.in);
		int a = s.nextInt();
		int [] nums = new int[a];
		for (int i = 0; i <a; i++) {
			int ai = s.nextInt();
			nums[i]=ai;
		}
		Arrays.sort(nums);
		double fix = nums[0];
		for (int i = 1; i <a; i++) {
			fix = (fix+nums[i])/2;
		}
		System.out.println(fix);
		

	} Scanner s = new Scanner(System.in); s new Scanner(System.in) int a = s.nextInt(); a s.nextInt() s.nextInt s int [] nums = new int[a]; nums new int[a] a for (int i = 0; i <a; i++) {
			int ai = s.nextInt();
			nums[i]=ai;
		} int i = 0; int i = 0; i 0 i <a i a i++ i++ i {
			int ai = s.nextInt();
			nums[i]=ai;
		} {
			int ai = s.nextInt();
			nums[i]=ai;
		} int ai = s.nextInt(); ai s.nextInt() s.nextInt s nums[i]=ai nums[i] nums i ai Arrays.sort(nums) Arrays.sort Arrays nums double fix = nums[0]; fix nums[0] nums 0 for (int i = 1; i <a; i++) {
			fix = (fix+nums[i])/2;
		} int i = 1; int i = 1; i 1 i <a i a i++ i++ i {
			fix = (fix+nums[i])/2;
		} {
			fix = (fix+nums[i])/2;
		} fix = (fix+nums[i])/2 fix (fix+nums[i])/2 (fix+nums[i]) fix nums[i] nums i 2 System.out.println(fix) System.out.println System.out System System.out fix String[] args args public class Main {

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

	}

} public class Main {

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

	}

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

public class Main {

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

	}

}
