import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        int N=sc.nextInt();
        int A[];
        A=new int[N];
        for(int i=0;i<N;i++) A[i]=sc.nextInt();
        Arrays.sort(A);
        double ans=A[0];
        for(int i=1;i<N;i++) ans=(ans+A[i])/2;
        System.out.printf("%.10f\n",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