import java.util.*;

public class Main {
	Scanner sc;
	int N;
	int[] v;

	public Main() {
		sc = new Scanner(System.in);
	}
	
	private void calc() {
		N = sc.nextInt();
		v = new int[N];
		for (int i = 0; i < N; i++) v[i] = sc.nextInt();
		
		Arrays.sort(v);
		double ans = (double)v[0];
		for (int i = 1; i < N; i++) ans = (ans + v[i])/2d;
		
		System.out.println(ans);
		System.out.flush();
	}

	public static void main(String[] args) {
		new Main().calc();
	}

} import java.util.*; util.* java public class Main {
	Scanner sc;
	int N;
	int[] v;

	public Main() {
		sc = new Scanner(System.in);
	}
	
	private void calc() {
		N = sc.nextInt();
		v = new int[N];
		for (int i = 0; i < N; i++) v[i] = sc.nextInt();
		
		Arrays.sort(v);
		double ans = (double)v[0];
		for (int i = 1; i < N; i++) ans = (ans + v[i])/2d;
		
		System.out.println(ans);
		System.out.flush();
	}

	public static void main(String[] args) {
		new Main().calc();
	}

} Main Scanner sc; sc int N; N int[] v; v public Main() {
		sc = new Scanner(System.in);
	} Main {
		sc = new Scanner(System.in);
	} sc = new Scanner(System.in) sc new Scanner(System.in) private void calc() {
		N = sc.nextInt();
		v = new int[N];
		for (int i = 0; i < N; i++) v[i] = sc.nextInt();
		
		Arrays.sort(v);
		double ans = (double)v[0];
		for (int i = 1; i < N; i++) ans = (ans + v[i])/2d;
		
		System.out.println(ans);
		System.out.flush();
	} calc {
		N = sc.nextInt();
		v = new int[N];
		for (int i = 0; i < N; i++) v[i] = sc.nextInt();
		
		Arrays.sort(v);
		double ans = (double)v[0];
		for (int i = 1; i < N; i++) ans = (ans + v[i])/2d;
		
		System.out.println(ans);
		System.out.flush();
	} N = sc.nextInt() N sc.nextInt() sc.nextInt sc v = new int[N] v new int[N] N for (int i = 0; i < N; i++) v[i] = sc.nextInt(); int i = 0; int i = 0; i 0 i < N i N i++ i++ i v[i] = sc.nextInt(); v[i] = sc.nextInt() v[i] v i sc.nextInt() sc.nextInt sc Arrays.sort(v) Arrays.sort Arrays v double ans = (double)v[0]; ans (double)v[0] v 0 for (int i = 1; i < N; i++) ans = (ans + v[i])/2d; int i = 1; int i = 1; i 1 i < N i N i++ i++ i ans = (ans + v[i])/2d; ans = (ans + v[i])/2d ans (ans + v[i])/2d (ans + v[i]) ans v[i] v i 2d System.out.println(ans) System.out.println System.out System System.out ans System.out.flush() System.out.flush System.out System System.out public static void main(String[] args) {
		new Main().calc();
	} main {
		new Main().calc();
	} new Main().calc() new Main().calc new Main() String[] args args public class Main {
	Scanner sc;
	int N;
	int[] v;

	public Main() {
		sc = new Scanner(System.in);
	}
	
	private void calc() {
		N = sc.nextInt();
		v = new int[N];
		for (int i = 0; i < N; i++) v[i] = sc.nextInt();
		
		Arrays.sort(v);
		double ans = (double)v[0];
		for (int i = 1; i < N; i++) ans = (ans + v[i])/2d;
		
		System.out.println(ans);
		System.out.flush();
	}

	public static void main(String[] args) {
		new Main().calc();
	}

} public class Main {
	Scanner sc;
	int N;
	int[] v;

	public Main() {
		sc = new Scanner(System.in);
	}
	
	private void calc() {
		N = sc.nextInt();
		v = new int[N];
		for (int i = 0; i < N; i++) v[i] = sc.nextInt();
		
		Arrays.sort(v);
		double ans = (double)v[0];
		for (int i = 1; i < N; i++) ans = (ans + v[i])/2d;
		
		System.out.println(ans);
		System.out.flush();
	}

	public static void main(String[] args) {
		new Main().calc();
	}

} Main
import java.util.*;

public class Main {
	Scanner sc;
	int N;
	int[] v;

	public Main() {
		sc = new Scanner(System.in);
	}
	
	private void calc() {
		N = sc.nextInt();
		v = new int[N];
		for (int i = 0; i < N; i++) v[i] = sc.nextInt();
		
		Arrays.sort(v);
		double ans = (double)v[0];
		for (int i = 1; i < N; i++) ans = (ans + v[i])/2d;
		
		System.out.println(ans);
		System.out.flush();
	}

	public static void main(String[] args) {
		new Main().calc();
	}

}