import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		List<Double> list = new ArrayList<Double>();
		for (int i = 0; i < N; i++) {
			list.add(Double.parseDouble(sc.next()));
		}
		
		Collections.sort(list);
		
		double ans = list.get(0);
		list.remove(0);
		
		for (double v : list) {
			ans = ans/2 + v/2;
		}

		PrintWriter out = new PrintWriter(System.out);
		out.println(ans);
		out.flush();

	}

} import java.io.PrintWriter; PrintWriter java.io import java.util.ArrayList; ArrayList java.util import java.util.Collections; Collections java.util import java.util.List; List java.util import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		List<Double> list = new ArrayList<Double>();
		for (int i = 0; i < N; i++) {
			list.add(Double.parseDouble(sc.next()));
		}
		
		Collections.sort(list);
		
		double ans = list.get(0);
		list.remove(0);
		
		for (double v : list) {
			ans = ans/2 + v/2;
		}

		PrintWriter out = new PrintWriter(System.out);
		out.println(ans);
		out.flush();

	}

} Main public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		List<Double> list = new ArrayList<Double>();
		for (int i = 0; i < N; i++) {
			list.add(Double.parseDouble(sc.next()));
		}
		
		Collections.sort(list);
		
		double ans = list.get(0);
		list.remove(0);
		
		for (double v : list) {
			ans = ans/2 + v/2;
		}

		PrintWriter out = new PrintWriter(System.out);
		out.println(ans);
		out.flush();

	} main {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		List<Double> list = new ArrayList<Double>();
		for (int i = 0; i < N; i++) {
			list.add(Double.parseDouble(sc.next()));
		}
		
		Collections.sort(list);
		
		double ans = list.get(0);
		list.remove(0);
		
		for (double v : list) {
			ans = ans/2 + v/2;
		}

		PrintWriter out = new PrintWriter(System.out);
		out.println(ans);
		out.flush();

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = Integer.parseInt(sc.next()); N Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next sc List<Double> list = new ArrayList<Double>(); list new ArrayList<Double>() for (int i = 0; i < N; i++) {
			list.add(Double.parseDouble(sc.next()));
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			list.add(Double.parseDouble(sc.next()));
		} {
			list.add(Double.parseDouble(sc.next()));
		} list.add(Double.parseDouble(sc.next())) list.add list Double.parseDouble(sc.next()) Double.parseDouble Double sc.next() sc.next sc Collections.sort(list) Collections.sort Collections list double ans = list.get(0); ans list.get(0) list.get list 0 list.remove(0) list.remove list 0 for (double v : list) {
			ans = ans/2 + v/2;
		} double v list {
			ans = ans/2 + v/2;
		} {
			ans = ans/2 + v/2;
		} ans = ans/2 + v/2 ans ans/2 + v/2 ans/2 ans 2 v/2 v 2 PrintWriter out = new PrintWriter(System.out); out new PrintWriter(System.out) out.println(ans) out.println out ans out.flush() out.flush out String[] args args public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		List<Double> list = new ArrayList<Double>();
		for (int i = 0; i < N; i++) {
			list.add(Double.parseDouble(sc.next()));
		}
		
		Collections.sort(list);
		
		double ans = list.get(0);
		list.remove(0);
		
		for (double v : list) {
			ans = ans/2 + v/2;
		}

		PrintWriter out = new PrintWriter(System.out);
		out.println(ans);
		out.flush();

	}

} public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		List<Double> list = new ArrayList<Double>();
		for (int i = 0; i < N; i++) {
			list.add(Double.parseDouble(sc.next()));
		}
		
		Collections.sort(list);
		
		double ans = list.get(0);
		list.remove(0);
		
		for (double v : list) {
			ans = ans/2 + v/2;
		}

		PrintWriter out = new PrintWriter(System.out);
		out.println(ans);
		out.flush();

	}

} Main
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		List<Double> list = new ArrayList<Double>();
		for (int i = 0; i < N; i++) {
			list.add(Double.parseDouble(sc.next()));
		}
		
		Collections.sort(list);
		
		double ans = list.get(0);
		list.remove(0);
		
		for (double v : list) {
			ans = ans/2 + v/2;
		}

		PrintWriter out = new PrintWriter(System.out);
		out.println(ans);
		out.flush();

	}

}
