import java.util.*;
 
public class Main{
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    int N = sc.nextInt();
    int v[] = new int[N];
    for(int i=0; i<N; i++){
      v[i] = sc.nextInt();
    }
    Arrays.sort(v);
    double value = v[0];
    for(int i=1; i<N; i++){
      value = (value + v[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