import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

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

		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		ArrayList<Double> aList = new ArrayList<>();
		
		for(int i = 1; i <= N; i++) {
			aList.add(sc.nextDouble());
		}
		
		//　昇順でソート
		Collections.sort(aList);

		//　前から順に合成
		double ans = aList.get(0);
		for(int i = 1; i < aList.size(); i++) {
			ans = (ans + aList.get(i)) / 2;
		}

		System.out.println(ans);
		sc.close();
	}
} import java.util.ArrayList; ArrayList java.util import java.util.Collections; Collections 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();
		ArrayList<Double> aList = new ArrayList<>();
		
		for(int i = 1; i <= N; i++) {
			aList.add(sc.nextDouble());
		}
		
		//　昇順でソート
		Collections.sort(aList);

		//　前から順に合成
		double ans = aList.get(0);
		for(int i = 1; i < aList.size(); i++) {
			ans = (ans + aList.get(i)) / 2;
		}

		System.out.println(ans);
		sc.close();
	}
} Main public static void main(String[] args){

		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		ArrayList<Double> aList = new ArrayList<>();
		
		for(int i = 1; i <= N; i++) {
			aList.add(sc.nextDouble());
		}
		
		//　昇順でソート
		Collections.sort(aList);

		//　前から順に合成
		double ans = aList.get(0);
		for(int i = 1; i < aList.size(); i++) {
			ans = (ans + aList.get(i)) / 2;
		}

		System.out.println(ans);
		sc.close();
	} main {

		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		ArrayList<Double> aList = new ArrayList<>();
		
		for(int i = 1; i <= N; i++) {
			aList.add(sc.nextDouble());
		}
		
		//　昇順でソート
		Collections.sort(aList);

		//　前から順に合成
		double ans = aList.get(0);
		for(int i = 1; i < aList.size(); i++) {
			ans = (ans + aList.get(i)) / 2;
		}

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

		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		ArrayList<Double> aList = new ArrayList<>();
		
		for(int i = 1; i <= N; i++) {
			aList.add(sc.nextDouble());
		}
		
		//　昇順でソート
		Collections.sort(aList);

		//　前から順に合成
		double ans = aList.get(0);
		for(int i = 1; i < aList.size(); i++) {
			ans = (ans + aList.get(i)) / 2;
		}

		System.out.println(ans);
		sc.close();
	}
} public class Main {
	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		ArrayList<Double> aList = new ArrayList<>();
		
		for(int i = 1; i <= N; i++) {
			aList.add(sc.nextDouble());
		}
		
		//　昇順でソート
		Collections.sort(aList);

		//　前から順に合成
		double ans = aList.get(0);
		for(int i = 1; i < aList.size(); i++) {
			ans = (ans + aList.get(i)) / 2;
		}

		System.out.println(ans);
		sc.close();
	}
} Main
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

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

		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		ArrayList<Double> aList = new ArrayList<>();
		
		for(int i = 1; i <= N; i++) {
			aList.add(sc.nextDouble());
		}
		
		//　昇順でソート
		Collections.sort(aList);

		//　前から順に合成
		double ans = aList.get(0);
		for(int i = 1; i < aList.size(); i++) {
			ans = (ans + aList.get(i)) / 2;
		}

		System.out.println(ans);
		sc.close();
	}
}
