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){

		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int n = sc.nextInt();

		//double[] a = new double[n];
		double temp =0;
		List<Double> list = new ArrayList<>();
		for(int i=0;i<n;i++) {
			list.add(sc.nextDouble());
		}
		Collections.sort(list);

		temp = (list.get(0)+list.get(1))/2;
		for(int i =2; i<n;i++) {
			temp = (temp+list.get(i))/2;
		}
		System.out.println(temp);
	}

	} 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){

		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int n = sc.nextInt();

		//double[] a = new double[n];
		double temp =0;
		List<Double> list = new ArrayList<>();
		for(int i=0;i<n;i++) {
			list.add(sc.nextDouble());
		}
		Collections.sort(list);

		temp = (list.get(0)+list.get(1))/2;
		for(int i =2; i<n;i++) {
			temp = (temp+list.get(i))/2;
		}
		System.out.println(temp);
	}

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

		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int n = sc.nextInt();

		//double[] a = new double[n];
		double temp =0;
		List<Double> list = new ArrayList<>();
		for(int i=0;i<n;i++) {
			list.add(sc.nextDouble());
		}
		Collections.sort(list);

		temp = (list.get(0)+list.get(1))/2;
		for(int i =2; i<n;i++) {
			temp = (temp+list.get(i))/2;
		}
		System.out.println(temp);
	} main {

		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int n = sc.nextInt();

		//double[] a = new double[n];
		double temp =0;
		List<Double> list = new ArrayList<>();
		for(int i=0;i<n;i++) {
			list.add(sc.nextDouble());
		}
		Collections.sort(list);

		temp = (list.get(0)+list.get(1))/2;
		for(int i =2; i<n;i++) {
			temp = (temp+list.get(i))/2;
		}
		System.out.println(temp);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc double temp =0; temp 0 List<Double> list = new ArrayList<>(); list new ArrayList<>() for(int i=0;i<n;i++) {
			list.add(sc.nextDouble());
		} int i=0; int i=0; i 0 i<n i n i++ i++ i {
			list.add(sc.nextDouble());
		} {
			list.add(sc.nextDouble());
		} list.add(sc.nextDouble()) list.add list sc.nextDouble() sc.nextDouble sc Collections.sort(list) Collections.sort Collections list temp = (list.get(0)+list.get(1))/2 temp (list.get(0)+list.get(1))/2 (list.get(0)+list.get(1)) list.get(0) list.get list 0 list.get(1) list.get list 1 2 for(int i =2; i<n;i++) {
			temp = (temp+list.get(i))/2;
		} int i =2; int i =2; i 2 i<n i n i++ i++ i {
			temp = (temp+list.get(i))/2;
		} {
			temp = (temp+list.get(i))/2;
		} temp = (temp+list.get(i))/2 temp (temp+list.get(i))/2 (temp+list.get(i)) temp list.get(i) list.get list i 2 System.out.println(temp) System.out.println System.out System System.out temp String[] args args public class Main {
	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int n = sc.nextInt();

		//double[] a = new double[n];
		double temp =0;
		List<Double> list = new ArrayList<>();
		for(int i=0;i<n;i++) {
			list.add(sc.nextDouble());
		}
		Collections.sort(list);

		temp = (list.get(0)+list.get(1))/2;
		for(int i =2; i<n;i++) {
			temp = (temp+list.get(i))/2;
		}
		System.out.println(temp);
	}

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

		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int n = sc.nextInt();

		//double[] a = new double[n];
		double temp =0;
		List<Double> list = new ArrayList<>();
		for(int i=0;i<n;i++) {
			list.add(sc.nextDouble());
		}
		Collections.sort(list);

		temp = (list.get(0)+list.get(1))/2;
		for(int i =2; i<n;i++) {
			temp = (temp+list.get(i))/2;
		}
		System.out.println(temp);
	}

	} Main
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){

		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int n = sc.nextInt();

		//double[] a = new double[n];
		double temp =0;
		List<Double> list = new ArrayList<>();
		for(int i=0;i<n;i++) {
			list.add(sc.nextDouble());
		}
		Collections.sort(list);

		temp = (list.get(0)+list.get(1))/2;
		for(int i =2; i<n;i++) {
			temp = (temp+list.get(i))/2;
		}
		System.out.println(temp);
	}

	}