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

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		double[] v = new double[n];
	
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		
		Arrays.sort(v);

		for(int i = 0; i < n-1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2;
		}
		
		System.out.println(v[n-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 sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		double[] v = new double[n];
	
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		
		Arrays.sort(v);

		for(int i = 0; i < n-1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2;
		}
		
		System.out.println(v[n-1]);

	}
} Main public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		double[] v = new double[n];
	
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		
		Arrays.sort(v);

		for(int i = 0; i < n-1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2;
		}
		
		System.out.println(v[n-1]);

	} main {

		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		double[] v = new double[n];
	
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		
		Arrays.sort(v);

		for(int i = 0; i < n-1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2;
		}
		
		System.out.println(v[n-1]);

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc double[] v = new double[n]; v new double[n] n for(int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			v[i] = sc.nextDouble();
		} {
			v[i] = sc.nextDouble();
		} v[i] = sc.nextDouble() v[i] v i sc.nextDouble() sc.nextDouble sc Arrays.sort(v) Arrays.sort Arrays v for(int i = 0; i < n-1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2;
		} int i = 0; int i = 0; i 0 i < n-1 i n-1 n 1 i++ i++ i {
			v[i+1] = (v[i] + v[i+1]) / 2;
		} {
			v[i+1] = (v[i] + v[i+1]) / 2;
		} v[i+1] = (v[i] + v[i+1]) / 2 v[i+1] v i+1 i 1 (v[i] + v[i+1]) / 2 (v[i] + v[i+1]) v[i] v i v[i+1] v i+1 i 1 2 System.out.println(v[n-1]) System.out.println System.out System System.out v[n-1] v n-1 n 1 String[] args args public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		double[] v = new double[n];
	
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		
		Arrays.sort(v);

		for(int i = 0; i < n-1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2;
		}
		
		System.out.println(v[n-1]);

	}
} public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		double[] v = new double[n];
	
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		
		Arrays.sort(v);

		for(int i = 0; i < n-1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2;
		}
		
		System.out.println(v[n-1]);

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

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		double[] v = new double[n];
	
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		
		Arrays.sort(v);

		for(int i = 0; i < n-1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2;
		}
		
		System.out.println(v[n-1]);

	}
}
