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