import java.util.*;
public class Main{

 public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] list = new int[n];
        for(int i=0;i<n;i++){
            list[i] = sc.nextInt();
        }
        Arrays.sort(list);

        for(int i=0;i<n;i++){
        }
        double result = (double)list[0];
        for(int j=1;j<n;j++){
            result = (double)((result + list[j]) /2);
        }
        System.out.println(result);
    }

}
/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