import java.io.*;
import java.util.*;
public class Main{
  public static void main(String[]args){
  Scanner sc=new Scanner(System.in);
    int n=sc.nextInt();
    int[] a=new int[n];
  	for(int i=0;i<n;i++)a[i]=sc.nextInt();
    Arrays.sort(a);
    double value=a[0];
    for(int i=0;i<n;i++){
   	value=(value+a[i])/2;
    }
    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