import java.util.Scanner;
import java.util.Arrays;
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 output = a[0];
      for(int i = 1 ; i < N ; i++) {
      	output = (double)((output + (double) a[i]) / 2);
      }
      System.out.println(output);
      
    }
}
/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