import java.util.Arrays;
import java.util.Scanner;
 
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		int n = sc.nextInt();
		int v[] = new int[n];
		double sum = 0;
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		sum = (v[0] + v[1]) / 2.0;
		for (int i = 2; i < n; i++) {
			sum = (sum + v[i]) / 2.0;
		}
		System.out.println(sum);
	}
} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		int n = sc.nextInt();
		int v[] = new int[n];
		double sum = 0;
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		sum = (v[0] + v[1]) / 2.0;
		for (int i = 2; i < n; i++) {
			sum = (sum + v[i]) / 2.0;
		}
		System.out.println(sum);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		int n = sc.nextInt();
		int v[] = new int[n];
		double sum = 0;
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		sum = (v[0] + v[1]) / 2.0;
		for (int i = 2; i < n; i++) {
			sum = (sum + v[i]) / 2.0;
		}
		System.out.println(sum);
	} main {
		Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		int n = sc.nextInt();
		int v[] = new int[n];
		double sum = 0;
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		sum = (v[0] + v[1]) / 2.0;
		for (int i = 2; i < n; i++) {
			sum = (sum + v[i]) / 2.0;
		}
		System.out.println(sum);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) StringBuilder sb = new StringBuilder(); sb new StringBuilder() int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int v[] = new int[n]; v new int[n] n double sum = 0; sum 0 for (int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < n i n 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 sum = (v[0] + v[1]) / 2.0 sum (v[0] + v[1]) / 2.0 (v[0] + v[1]) v[0] v 0 v[1] v 1 2.0 for (int i = 2; i < n; i++) {
			sum = (sum + v[i]) / 2.0;
		} int i = 2; int i = 2; i 2 i < n i n i++ i++ i {
			sum = (sum + v[i]) / 2.0;
		} {
			sum = (sum + v[i]) / 2.0;
		} sum = (sum + v[i]) / 2.0 sum (sum + v[i]) / 2.0 (sum + v[i]) sum v[i] v i 2.0 System.out.println(sum) System.out.println System.out System System.out sum String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		int n = sc.nextInt();
		int v[] = new int[n];
		double sum = 0;
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		sum = (v[0] + v[1]) / 2.0;
		for (int i = 2; i < n; i++) {
			sum = (sum + v[i]) / 2.0;
		}
		System.out.println(sum);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		int n = sc.nextInt();
		int v[] = new int[n];
		double sum = 0;
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		sum = (v[0] + v[1]) / 2.0;
		for (int i = 2; i < n; i++) {
			sum = (sum + v[i]) / 2.0;
		}
		System.out.println(sum);
	}
} Main
import java.util.Arrays;
import java.util.Scanner;
 
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		StringBuilder sb = new StringBuilder();
		int n = sc.nextInt();
		int v[] = new int[n];
		double sum = 0;
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		sum = (v[0] + v[1]) / 2.0;
		for (int i = 2; i < n; i++) {
			sum = (sum + v[i]) / 2.0;
		}
		System.out.println(sum);
	}
}