import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<Integer> v = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            v.add(sc.nextInt());
        }
        sc.close();
        Collections.sort(v);

        double value = v.remove(0);
        for (int i = 0; i < n - 1; i++) {
            value = (value + v.remove(0)) / 2.0;
        }
        System.out.println(value);
    }

}

/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