import java.util.*; 

class Main{
public static void main(String[] args){
	Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
       
  		int[] v=new int[n];
		for(int c=0;c<n;c++){
    		v[c]=sc.nextInt();
    	}
  	Arrays.sort(v);
  	double ans=(double)v[0];
    
 	for(int d=1;d<n;d++){
      ans=(ans+v[d])/2;
    
    }

    	System.out.println(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