import java.util.*;
public class Main {

	public static void main(String[] ble){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		for(int i = 0; i < n; i++){
			arr[i] = sc.nextInt();
		}
		Arrays.sort(arr);
		double res = arr[0] + arr[1];
		res /= 2;
		for(int i = 2; i < n; i++){
			res += arr[i];
			res /= 2;
		}
		System.out.println(res);
	}
} import java.util.*; util.* java public class Main {

	public static void main(String[] ble){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		for(int i = 0; i < n; i++){
			arr[i] = sc.nextInt();
		}
		Arrays.sort(arr);
		double res = arr[0] + arr[1];
		res /= 2;
		for(int i = 2; i < n; i++){
			res += arr[i];
			res /= 2;
		}
		System.out.println(res);
	}
} Main public static void main(String[] ble){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		for(int i = 0; i < n; i++){
			arr[i] = sc.nextInt();
		}
		Arrays.sort(arr);
		double res = arr[0] + arr[1];
		res /= 2;
		for(int i = 2; i < n; i++){
			res += arr[i];
			res /= 2;
		}
		System.out.println(res);
	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		for(int i = 0; i < n; i++){
			arr[i] = sc.nextInt();
		}
		Arrays.sort(arr);
		double res = arr[0] + arr[1];
		res /= 2;
		for(int i = 2; i < n; i++){
			res += arr[i];
			res /= 2;
		}
		System.out.println(res);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int[] arr = new int[n]; arr new int[n] n for(int i = 0; i < n; i++){
			arr[i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			arr[i] = sc.nextInt();
		} {
			arr[i] = sc.nextInt();
		} arr[i] = sc.nextInt() arr[i] arr i sc.nextInt() sc.nextInt sc Arrays.sort(arr) Arrays.sort Arrays arr double res = arr[0] + arr[1]; res arr[0] + arr[1] arr[0] arr 0 arr[1] arr 1 res /= 2 res 2 for(int i = 2; i < n; i++){
			res += arr[i];
			res /= 2;
		} int i = 2; int i = 2; i 2 i < n i n i++ i++ i {
			res += arr[i];
			res /= 2;
		} {
			res += arr[i];
			res /= 2;
		} res += arr[i] res arr[i] arr i res /= 2 res 2 System.out.println(res) System.out.println System.out System System.out res String[] ble ble public class Main {

	public static void main(String[] ble){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		for(int i = 0; i < n; i++){
			arr[i] = sc.nextInt();
		}
		Arrays.sort(arr);
		double res = arr[0] + arr[1];
		res /= 2;
		for(int i = 2; i < n; i++){
			res += arr[i];
			res /= 2;
		}
		System.out.println(res);
	}
} public class Main {

	public static void main(String[] ble){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		for(int i = 0; i < n; i++){
			arr[i] = sc.nextInt();
		}
		Arrays.sort(arr);
		double res = arr[0] + arr[1];
		res /= 2;
		for(int i = 2; i < n; i++){
			res += arr[i];
			res /= 2;
		}
		System.out.println(res);
	}
} Main
import java.util.*;
public class Main {

	public static void main(String[] ble){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[] arr = new int[n];
		for(int i = 0; i < n; i++){
			arr[i] = sc.nextInt();
		}
		Arrays.sort(arr);
		double res = arr[0] + arr[1];
		res /= 2;
		for(int i = 2; i < n; i++){
			res += arr[i];
			res /= 2;
		}
		System.out.println(res);
	}
}
