
import java.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;

public class Main {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        
        Scanner s = new Scanner(System.in);
        int n = s.nextInt();
        
        ArrayList<Integer> vs = new ArrayList<>();
        
        for (int i = 0; i < n; i ++) {
            vs.add(s.nextInt());
        }
        
        Collections.sort(vs);
        
        double output = vs.get(0);
        
        for (int i = 1; i < vs.size(); i ++) {
            output = (double) (output + vs.get(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