import java.util.Scanner;
import java.util.*;
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 sum = 0;
    for(int j=0;j<N;j++){
      if(j==0){
       sum = v[j];
      }else{
       sum = (sum+v[j])/2.0;
      }
    }
    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