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

class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int t = scan.nextInt();
        int[] ar = new int[t];
        for (int i = 0; i < t; i++) {
            ar[i] = scan.nextInt();
        }

        Arrays.sort(ar);
        double result = ar[0];
        for (int i = 0; i < ar.length; i++) {
            result = (result+ar[i])/2;
        }

        System.out.println(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