
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[] V = new int[N];

		for (int i = 0; i < N; i++) {
			V[i] = sc.nextInt();
		}

		Arrays.sort(V);

		double result = V[0];
		for (int i = 1; i < N; i++) {
			result = (result + V[i]) / 2;
		}

		System.out.print(result);

	}
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz