import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int A[] = new int[N];
		for (int i=0;i<N;i++) {
			A[i]= sc.nextInt();
		}
		Arrays.parallelSort(A);
		double now =(A[0]+A[1])/2.0;
		for (int i=2;i<N;i++) {
			now = (A[i]+now)/2.0;
		}
		System.out.println(now);
	}
} 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);
		int N = sc.nextInt();
		int A[] = new int[N];
		for (int i=0;i<N;i++) {
			A[i]= sc.nextInt();
		}
		Arrays.parallelSort(A);
		double now =(A[0]+A[1])/2.0;
		for (int i=2;i<N;i++) {
			now = (A[i]+now)/2.0;
		}
		System.out.println(now);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int A[] = new int[N];
		for (int i=0;i<N;i++) {
			A[i]= sc.nextInt();
		}
		Arrays.parallelSort(A);
		double now =(A[0]+A[1])/2.0;
		for (int i=2;i<N;i++) {
			now = (A[i]+now)/2.0;
		}
		System.out.println(now);
	} main {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int A[] = new int[N];
		for (int i=0;i<N;i++) {
			A[i]= sc.nextInt();
		}
		Arrays.parallelSort(A);
		double now =(A[0]+A[1])/2.0;
		for (int i=2;i<N;i++) {
			now = (A[i]+now)/2.0;
		}
		System.out.println(now);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int A[] = new int[N]; A new int[N] N for (int i=0;i<N;i++) {
			A[i]= sc.nextInt();
		} int i=0; int i=0; i 0 i<N i N i++ i++ i {
			A[i]= sc.nextInt();
		} {
			A[i]= sc.nextInt();
		} A[i]= sc.nextInt() A[i] A i sc.nextInt() sc.nextInt sc Arrays.parallelSort(A) Arrays.parallelSort Arrays A double now =(A[0]+A[1])/2.0; now (A[0]+A[1])/2.0 (A[0]+A[1]) A[0] A 0 A[1] A 1 2.0 for (int i=2;i<N;i++) {
			now = (A[i]+now)/2.0;
		} int i=2; int i=2; i 2 i<N i N i++ i++ i {
			now = (A[i]+now)/2.0;
		} {
			now = (A[i]+now)/2.0;
		} now = (A[i]+now)/2.0 now (A[i]+now)/2.0 (A[i]+now) A[i] A i now 2.0 System.out.println(now) System.out.println System.out System System.out now String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int A[] = new int[N];
		for (int i=0;i<N;i++) {
			A[i]= sc.nextInt();
		}
		Arrays.parallelSort(A);
		double now =(A[0]+A[1])/2.0;
		for (int i=2;i<N;i++) {
			now = (A[i]+now)/2.0;
		}
		System.out.println(now);
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int A[] = new int[N];
		for (int i=0;i<N;i++) {
			A[i]= sc.nextInt();
		}
		Arrays.parallelSort(A);
		double now =(A[0]+A[1])/2.0;
		for (int i=2;i<N;i++) {
			now = (A[i]+now)/2.0;
		}
		System.out.println(now);
	}
} Main
import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int A[] = new int[N];
		for (int i=0;i<N;i++) {
			A[i]= sc.nextInt();
		}
		Arrays.parallelSort(A);
		double now =(A[0]+A[1])/2.0;
		for (int i=2;i<N;i++) {
			now = (A[i]+now)/2.0;
		}
		System.out.println(now);
	}
}