import java.util.*;
import java.io.*;
import java.math.BigInteger;

public class Main {


	
	public static void main(String[] args)throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(System.out);
		
		int n = Integer.parseInt(br.readLine());
		
		Double[] arr = new Double[n];
		
		StringTokenizer st1 = new StringTokenizer(br.readLine());
		
		for(int i = 0 ; i < n ;i++)
			arr[i] = Double.parseDouble(st1.nextToken());
		
		Arrays.sort(arr);
		
		double res = arr[0];
		
		for(int i = 1 ; i < n ; i++)
		{
			res = (res + arr[i])/2.0;
			
		}
		
		out.println(res);
		
		out.flush();
		out.close();
	}
	
	
	


} import java.util.*; util.* java import java.io.*; io.* java import java.math.BigInteger; BigInteger java.math public class Main {


	
	public static void main(String[] args)throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(System.out);
		
		int n = Integer.parseInt(br.readLine());
		
		Double[] arr = new Double[n];
		
		StringTokenizer st1 = new StringTokenizer(br.readLine());
		
		for(int i = 0 ; i < n ;i++)
			arr[i] = Double.parseDouble(st1.nextToken());
		
		Arrays.sort(arr);
		
		double res = arr[0];
		
		for(int i = 1 ; i < n ; i++)
		{
			res = (res + arr[i])/2.0;
			
		}
		
		out.println(res);
		
		out.flush();
		out.close();
	}
	
	
	


} Main public static void main(String[] args)throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(System.out);
		
		int n = Integer.parseInt(br.readLine());
		
		Double[] arr = new Double[n];
		
		StringTokenizer st1 = new StringTokenizer(br.readLine());
		
		for(int i = 0 ; i < n ;i++)
			arr[i] = Double.parseDouble(st1.nextToken());
		
		Arrays.sort(arr);
		
		double res = arr[0];
		
		for(int i = 1 ; i < n ; i++)
		{
			res = (res + arr[i])/2.0;
			
		}
		
		out.println(res);
		
		out.flush();
		out.close();
	} main {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(System.out);
		
		int n = Integer.parseInt(br.readLine());
		
		Double[] arr = new Double[n];
		
		StringTokenizer st1 = new StringTokenizer(br.readLine());
		
		for(int i = 0 ; i < n ;i++)
			arr[i] = Double.parseDouble(st1.nextToken());
		
		Arrays.sort(arr);
		
		double res = arr[0];
		
		for(int i = 1 ; i < n ; i++)
		{
			res = (res + arr[i])/2.0;
			
		}
		
		out.println(res);
		
		out.flush();
		out.close();
	} BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) int n = Integer.parseInt(br.readLine()); n Integer.parseInt(br.readLine()) Integer.parseInt Integer br.readLine() br.readLine br Double[] arr = new Double[n]; arr new Double[n] n StringTokenizer st1 = new StringTokenizer(br.readLine()); st1 new StringTokenizer(br.readLine()) for(int i = 0 ; i < n ;i++)
			arr[i] = Double.parseDouble(st1.nextToken()); int i = 0 ; int i = 0 ; i 0 i < n i n i++ i++ i arr[i] = Double.parseDouble(st1.nextToken()); arr[i] = Double.parseDouble(st1.nextToken()) arr[i] arr i Double.parseDouble(st1.nextToken()) Double.parseDouble Double st1.nextToken() st1.nextToken st1 Arrays.sort(arr) Arrays.sort Arrays arr double res = arr[0]; res arr[0] arr 0 for(int i = 1 ; i < n ; i++)
		{
			res = (res + arr[i])/2.0;
			
		} int i = 1 ; int i = 1 ; i 1 i < n i n i++ i++ i {
			res = (res + arr[i])/2.0;
			
		} {
			res = (res + arr[i])/2.0;
			
		} res = (res + arr[i])/2.0 res (res + arr[i])/2.0 (res + arr[i]) res arr[i] arr i 2.0 out.println(res) out.println out res out.flush() out.flush out out.close() out.close out String[] args args public class Main {


	
	public static void main(String[] args)throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(System.out);
		
		int n = Integer.parseInt(br.readLine());
		
		Double[] arr = new Double[n];
		
		StringTokenizer st1 = new StringTokenizer(br.readLine());
		
		for(int i = 0 ; i < n ;i++)
			arr[i] = Double.parseDouble(st1.nextToken());
		
		Arrays.sort(arr);
		
		double res = arr[0];
		
		for(int i = 1 ; i < n ; i++)
		{
			res = (res + arr[i])/2.0;
			
		}
		
		out.println(res);
		
		out.flush();
		out.close();
	}
	
	
	


} public class Main {


	
	public static void main(String[] args)throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(System.out);
		
		int n = Integer.parseInt(br.readLine());
		
		Double[] arr = new Double[n];
		
		StringTokenizer st1 = new StringTokenizer(br.readLine());
		
		for(int i = 0 ; i < n ;i++)
			arr[i] = Double.parseDouble(st1.nextToken());
		
		Arrays.sort(arr);
		
		double res = arr[0];
		
		for(int i = 1 ; i < n ; i++)
		{
			res = (res + arr[i])/2.0;
			
		}
		
		out.println(res);
		
		out.flush();
		out.close();
	}
	
	
	


} Main
import java.util.*;
import java.io.*;
import java.math.BigInteger;

public class Main {


	
	public static void main(String[] args)throws IOException
	{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		PrintWriter out = new PrintWriter(System.out);
		
		int n = Integer.parseInt(br.readLine());
		
		Double[] arr = new Double[n];
		
		StringTokenizer st1 = new StringTokenizer(br.readLine());
		
		for(int i = 0 ; i < n ;i++)
			arr[i] = Double.parseDouble(st1.nextToken());
		
		Arrays.sort(arr);
		
		double res = arr[0];
		
		for(int i = 1 ; i < n ; i++)
		{
			res = (res + arr[i])/2.0;
			
		}
		
		out.println(res);
		
		out.flush();
		out.close();
	}
	
	
	


}
