import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.nextLine());
		List<Double> v = new ArrayList<>();
		for (int i = 0; i < N; i++) {
			v.add(sc.nextDouble());
		}
		v.sort(null);
		while (v.size() > 1) {
			double vv = (v.remove(0) + v.remove(0)) / 2;
			v.add(0, vv);
		}
		System.out.println(v.get(0));
	}
} import java.util.ArrayList; ArrayList 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) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.nextLine());
		List<Double> v = new ArrayList<>();
		for (int i = 0; i < N; i++) {
			v.add(sc.nextDouble());
		}
		v.sort(null);
		while (v.size() > 1) {
			double vv = (v.remove(0) + v.remove(0)) / 2;
			v.add(0, vv);
		}
		System.out.println(v.get(0));
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.nextLine());
		List<Double> v = new ArrayList<>();
		for (int i = 0; i < N; i++) {
			v.add(sc.nextDouble());
		}
		v.sort(null);
		while (v.size() > 1) {
			double vv = (v.remove(0) + v.remove(0)) / 2;
			v.add(0, vv);
		}
		System.out.println(v.get(0));
	} main {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.nextLine());
		List<Double> v = new ArrayList<>();
		for (int i = 0; i < N; i++) {
			v.add(sc.nextDouble());
		}
		v.sort(null);
		while (v.size() > 1) {
			double vv = (v.remove(0) + v.remove(0)) / 2;
			v.add(0, vv);
		}
		System.out.println(v.get(0));
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = Integer.parseInt(sc.nextLine()); N Integer.parseInt(sc.nextLine()) Integer.parseInt Integer sc.nextLine() sc.nextLine sc List<Double> v = new ArrayList<>(); v new ArrayList<>() for (int i = 0; i < N; i++) {
			v.add(sc.nextDouble());
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			v.add(sc.nextDouble());
		} {
			v.add(sc.nextDouble());
		} v.add(sc.nextDouble()) v.add v sc.nextDouble() sc.nextDouble sc v.sort(null) v.sort v null while (v.size() > 1) {
			double vv = (v.remove(0) + v.remove(0)) / 2;
			v.add(0, vv);
		} v.size() > 1 v.size() v.size v 1 {
			double vv = (v.remove(0) + v.remove(0)) / 2;
			v.add(0, vv);
		} double vv = (v.remove(0) + v.remove(0)) / 2; vv (v.remove(0) + v.remove(0)) / 2 (v.remove(0) + v.remove(0)) v.remove(0) v.remove v 0 v.remove(0) v.remove v 0 2 v.add(0, vv) v.add v 0 vv System.out.println(v.get(0)) System.out.println System.out System System.out v.get(0) v.get v 0 String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.nextLine());
		List<Double> v = new ArrayList<>();
		for (int i = 0; i < N; i++) {
			v.add(sc.nextDouble());
		}
		v.sort(null);
		while (v.size() > 1) {
			double vv = (v.remove(0) + v.remove(0)) / 2;
			v.add(0, vv);
		}
		System.out.println(v.get(0));
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.nextLine());
		List<Double> v = new ArrayList<>();
		for (int i = 0; i < N; i++) {
			v.add(sc.nextDouble());
		}
		v.sort(null);
		while (v.size() > 1) {
			double vv = (v.remove(0) + v.remove(0)) / 2;
			v.add(0, vv);
		}
		System.out.println(v.get(0));
	}
} Main
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.nextLine());
		List<Double> v = new ArrayList<>();
		for (int i = 0; i < N; i++) {
			v.add(sc.nextDouble());
		}
		v.sort(null);
		while (v.size() > 1) {
			double vv = (v.remove(0) + v.remove(0)) / 2;
			v.add(0, vv);
		}
		System.out.println(v.get(0));
	}
}