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