import java.util.Arrays;
import java.util.Scanner;
 
public class Main {
 
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = Integer.valueOf(in.nextLine());
		double[] v = new double[n];
		for(int i = 0; i < n; i++)
			v[i] = Double.valueOf(in.next());

		Arrays.sort(v);
		double sum = v[0];
		for(int i = 1; i < n; i++)
			sum = (sum + v[i]) / 2;
		System.out.println(sum);
		
	}
} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
 
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = Integer.valueOf(in.nextLine());
		double[] v = new double[n];
		for(int i = 0; i < n; i++)
			v[i] = Double.valueOf(in.next());

		Arrays.sort(v);
		double sum = v[0];
		for(int i = 1; i < n; i++)
			sum = (sum + v[i]) / 2;
		System.out.println(sum);
		
	}
} Main public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = Integer.valueOf(in.nextLine());
		double[] v = new double[n];
		for(int i = 0; i < n; i++)
			v[i] = Double.valueOf(in.next());

		Arrays.sort(v);
		double sum = v[0];
		for(int i = 1; i < n; i++)
			sum = (sum + v[i]) / 2;
		System.out.println(sum);
		
	} main {
		Scanner in = new Scanner(System.in);
		int n = Integer.valueOf(in.nextLine());
		double[] v = new double[n];
		for(int i = 0; i < n; i++)
			v[i] = Double.valueOf(in.next());

		Arrays.sort(v);
		double sum = v[0];
		for(int i = 1; i < n; i++)
			sum = (sum + v[i]) / 2;
		System.out.println(sum);
		
	} Scanner in = new Scanner(System.in); in new Scanner(System.in) int n = Integer.valueOf(in.nextLine()); n Integer.valueOf(in.nextLine()) Integer.valueOf Integer in.nextLine() in.nextLine in double[] v = new double[n]; v new double[n] n for(int i = 0; i < n; i++)
			v[i] = Double.valueOf(in.next()); int i = 0; int i = 0; i 0 i < n i n i++ i++ i v[i] = Double.valueOf(in.next()); v[i] = Double.valueOf(in.next()) v[i] v i Double.valueOf(in.next()) Double.valueOf Double in.next() in.next in Arrays.sort(v) Arrays.sort Arrays v double sum = v[0]; sum v[0] v 0 for(int i = 1; i < n; i++)
			sum = (sum + v[i]) / 2; int i = 1; int i = 1; i 1 i < n i n i++ i++ i sum = (sum + v[i]) / 2; sum = (sum + v[i]) / 2 sum (sum + v[i]) / 2 (sum + v[i]) sum v[i] v i 2 System.out.println(sum) System.out.println System.out System System.out sum String[] args args public class Main {
 
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = Integer.valueOf(in.nextLine());
		double[] v = new double[n];
		for(int i = 0; i < n; i++)
			v[i] = Double.valueOf(in.next());

		Arrays.sort(v);
		double sum = v[0];
		for(int i = 1; i < n; i++)
			sum = (sum + v[i]) / 2;
		System.out.println(sum);
		
	}
} public class Main {
 
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = Integer.valueOf(in.nextLine());
		double[] v = new double[n];
		for(int i = 0; i < n; i++)
			v[i] = Double.valueOf(in.next());

		Arrays.sort(v);
		double sum = v[0];
		for(int i = 1; i < n; i++)
			sum = (sum + v[i]) / 2;
		System.out.println(sum);
		
	}
} Main
import java.util.Arrays;
import java.util.Scanner;
 
public class Main {
 
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = Integer.valueOf(in.nextLine());
		double[] v = new double[n];
		for(int i = 0; i < n; i++)
			v[i] = Double.valueOf(in.next());

		Arrays.sort(v);
		double sum = v[0];
		for(int i = 1; i < n; i++)
			sum = (sum + v[i]) / 2;
		System.out.println(sum);
		
	}
}