import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
    
		// 整数の入力
		int n = sc.nextInt();
       ArrayList<Integer> vList= new ArrayList<>();
         
		for(int i = 0; i < n; i++) {
          vList.add(sc.nextInt());
        }
        Collections.sort(vList);
        
        double ans = (double)vList.get(0);
        for (int i = 1; i < n; i++) {
          double sum = ans + (double)vList.get(i);
          ans = sum / 2;
        }
    
		// 出力
		System.out.println(ans);
	}
}
/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