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