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

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner jk = new Scanner(System.in);
		int n = jk.nextInt();
		int[] arr = new int[n];
		for (int i=0; i<n; i++)
		{
			arr[i] = jk.nextInt();
		}
		Arrays.sort(arr);
		double ans = (arr[0]+arr[1])/2.0;
		for (int i=2; i<n; i++)
		{
			ans = (ans+arr[i])/2.0;
		}
		System.out.println(ans);
		
	}

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

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner jk = new Scanner(System.in);
		int n = jk.nextInt();
		int[] arr = new int[n];
		for (int i=0; i<n; i++)
		{
			arr[i] = jk.nextInt();
		}
		Arrays.sort(arr);
		double ans = (arr[0]+arr[1])/2.0;
		for (int i=2; i<n; i++)
		{
			ans = (ans+arr[i])/2.0;
		}
		System.out.println(ans);
		
	}

} Main public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner jk = new Scanner(System.in);
		int n = jk.nextInt();
		int[] arr = new int[n];
		for (int i=0; i<n; i++)
		{
			arr[i] = jk.nextInt();
		}
		Arrays.sort(arr);
		double ans = (arr[0]+arr[1])/2.0;
		for (int i=2; i<n; i++)
		{
			ans = (ans+arr[i])/2.0;
		}
		System.out.println(ans);
		
	} main {
		// TODO Auto-generated method stub
		Scanner jk = new Scanner(System.in);
		int n = jk.nextInt();
		int[] arr = new int[n];
		for (int i=0; i<n; i++)
		{
			arr[i] = jk.nextInt();
		}
		Arrays.sort(arr);
		double ans = (arr[0]+arr[1])/2.0;
		for (int i=2; i<n; i++)
		{
			ans = (ans+arr[i])/2.0;
		}
		System.out.println(ans);
		
	} Scanner jk = new Scanner(System.in); jk new Scanner(System.in) int n = jk.nextInt(); n jk.nextInt() jk.nextInt jk int[] arr = new int[n]; arr new int[n] n for (int i=0; i<n; i++)
		{
			arr[i] = jk.nextInt();
		} int i=0; int i=0; i 0 i<n i n i++ i++ i {
			arr[i] = jk.nextInt();
		} {
			arr[i] = jk.nextInt();
		} arr[i] = jk.nextInt() arr[i] arr i jk.nextInt() jk.nextInt jk Arrays.sort(arr) Arrays.sort Arrays arr double ans = (arr[0]+arr[1])/2.0; ans (arr[0]+arr[1])/2.0 (arr[0]+arr[1]) arr[0] arr 0 arr[1] arr 1 2.0 for (int i=2; i<n; i++)
		{
			ans = (ans+arr[i])/2.0;
		} int i=2; int i=2; i 2 i<n i n i++ i++ i {
			ans = (ans+arr[i])/2.0;
		} {
			ans = (ans+arr[i])/2.0;
		} ans = (ans+arr[i])/2.0 ans (ans+arr[i])/2.0 (ans+arr[i]) ans arr[i] arr i 2.0 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner jk = new Scanner(System.in);
		int n = jk.nextInt();
		int[] arr = new int[n];
		for (int i=0; i<n; i++)
		{
			arr[i] = jk.nextInt();
		}
		Arrays.sort(arr);
		double ans = (arr[0]+arr[1])/2.0;
		for (int i=2; i<n; i++)
		{
			ans = (ans+arr[i])/2.0;
		}
		System.out.println(ans);
		
	}

} public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner jk = new Scanner(System.in);
		int n = jk.nextInt();
		int[] arr = new int[n];
		for (int i=0; i<n; i++)
		{
			arr[i] = jk.nextInt();
		}
		Arrays.sort(arr);
		double ans = (arr[0]+arr[1])/2.0;
		for (int i=2; i<n; i++)
		{
			ans = (ans+arr[i])/2.0;
		}
		System.out.println(ans);
		
	}

} Main

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

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner jk = new Scanner(System.in);
		int n = jk.nextInt();
		int[] arr = new int[n];
		for (int i=0; i<n; i++)
		{
			arr[i] = jk.nextInt();
		}
		Arrays.sort(arr);
		double ans = (arr[0]+arr[1])/2.0;
		for (int i=2; i<n; i++)
		{
			ans = (ans+arr[i])/2.0;
		}
		System.out.println(ans);
		
	}

}
