import java.util.*;
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int N = Integer.parseInt(sc.next()); 
    ArrayList<Double> v= new ArrayList<Double>();
    for (int i=0; i < N ;i++) {
      v.add(sc.nextDouble());
    }
    Collections.sort(v);
    double sum = v.get(0);
    for (int i=1; i < N ;i++) {
      sum = (sum + v.get(i))/2;
    }
    System.out.println(sum);
  }
}


/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