
import java.util.Arrays;
import java.util.Collections;
import java.util.PriorityQueue;
import java.util.Scanner;

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

import java.util.Arrays;
import java.util.Collections;
import java.util.PriorityQueue;
import java.util.Scanner;

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