import java.util.PriorityQueue;
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];
    PriorityQueue<Integer> queue = new PriorityQueue<>();
    for (int i = 0; i < N; i++) {
      queue.add(sc.nextInt());
    }
    float ans = queue.poll();
    while (!queue.isEmpty()) {
      ans = (ans + queue.poll()) / 2;
    }
    System.out.println(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