import java.util.Collections;
import java.util.LinkedList;
import java.util.Scanner;

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

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		LinkedList<Integer> inputs = new LinkedList<>();

		for(int i=0;i < n;i++) {
			inputs.add(sc.nextInt());
		}
		Collections.sort(inputs);

		double beforeParam = inputs.pop();
		for(int i=0;i < n - 1;i++) {
			beforeParam = (beforeParam + inputs.pop()) / 2;
		}

		System.out.println(beforeParam);

	}
} import java.util.Collections; Collections java.util import java.util.LinkedList; LinkedList 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();
		LinkedList<Integer> inputs = new LinkedList<>();

		for(int i=0;i < n;i++) {
			inputs.add(sc.nextInt());
		}
		Collections.sort(inputs);

		double beforeParam = inputs.pop();
		for(int i=0;i < n - 1;i++) {
			beforeParam = (beforeParam + inputs.pop()) / 2;
		}

		System.out.println(beforeParam);

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

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		LinkedList<Integer> inputs = new LinkedList<>();

		for(int i=0;i < n;i++) {
			inputs.add(sc.nextInt());
		}
		Collections.sort(inputs);

		double beforeParam = inputs.pop();
		for(int i=0;i < n - 1;i++) {
			beforeParam = (beforeParam + inputs.pop()) / 2;
		}

		System.out.println(beforeParam);

	} main {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		LinkedList<Integer> inputs = new LinkedList<>();

		for(int i=0;i < n;i++) {
			inputs.add(sc.nextInt());
		}
		Collections.sort(inputs);

		double beforeParam = inputs.pop();
		for(int i=0;i < n - 1;i++) {
			beforeParam = (beforeParam + inputs.pop()) / 2;
		}

		System.out.println(beforeParam);

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc LinkedList<Integer> inputs = new LinkedList<>(); inputs new LinkedList<>() for(int i=0;i < n;i++) {
			inputs.add(sc.nextInt());
		} int i=0; int i=0; i 0 i < n i n i++ i++ i {
			inputs.add(sc.nextInt());
		} {
			inputs.add(sc.nextInt());
		} inputs.add(sc.nextInt()) inputs.add inputs sc.nextInt() sc.nextInt sc Collections.sort(inputs) Collections.sort Collections inputs double beforeParam = inputs.pop(); beforeParam inputs.pop() inputs.pop inputs for(int i=0;i < n - 1;i++) {
			beforeParam = (beforeParam + inputs.pop()) / 2;
		} int i=0; int i=0; i 0 i < n - 1 i n - 1 n 1 i++ i++ i {
			beforeParam = (beforeParam + inputs.pop()) / 2;
		} {
			beforeParam = (beforeParam + inputs.pop()) / 2;
		} beforeParam = (beforeParam + inputs.pop()) / 2 beforeParam (beforeParam + inputs.pop()) / 2 (beforeParam + inputs.pop()) beforeParam inputs.pop() inputs.pop inputs 2 System.out.println(beforeParam) System.out.println System.out System System.out beforeParam String args[] args public class Main {
	public static void main(String args[]){

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		LinkedList<Integer> inputs = new LinkedList<>();

		for(int i=0;i < n;i++) {
			inputs.add(sc.nextInt());
		}
		Collections.sort(inputs);

		double beforeParam = inputs.pop();
		for(int i=0;i < n - 1;i++) {
			beforeParam = (beforeParam + inputs.pop()) / 2;
		}

		System.out.println(beforeParam);

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

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		LinkedList<Integer> inputs = new LinkedList<>();

		for(int i=0;i < n;i++) {
			inputs.add(sc.nextInt());
		}
		Collections.sort(inputs);

		double beforeParam = inputs.pop();
		for(int i=0;i < n - 1;i++) {
			beforeParam = (beforeParam + inputs.pop()) / 2;
		}

		System.out.println(beforeParam);

	}
} Main
import java.util.Collections;
import java.util.LinkedList;
import java.util.Scanner;

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

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		LinkedList<Integer> inputs = new LinkedList<>();

		for(int i=0;i < n;i++) {
			inputs.add(sc.nextInt());
		}
		Collections.sort(inputs);

		double beforeParam = inputs.pop();
		for(int i=0;i < n - 1;i++) {
			beforeParam = (beforeParam + inputs.pop()) / 2;
		}

		System.out.println(beforeParam);

	}
}