import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int n = s.nextInt();
        List<Double> l = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            l.add(s.nextDouble());
        }
        Collections.sort(l);
        double ch = 0;
        double ans = 0;
        for (double i : l) {
            if (ans == 0) {
                ans = i;
            }
            ans=(ans+i)/2;
        }
        System.out.print(ans);
    }
}
/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