import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        double[] ans=new double[n];
        for(int i=0;i<n;i++){
            ans[i]=sc.nextInt();
        }
        Arrays.sort(ans);
        for(int i=0;i<n-1;i++){
            ans[i+1]=(ans[i]+ans[i+1])/2;
        }
        System.out.println(ans[n-1]);
    }
    
    
}
/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