
import java.util.*;
import java.math.*;
public class Main {
	
	public static void main(String[] args){
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

	    List<Double> n1 = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            double d = (double)sc.nextInt();
			n1.add(d);
		}
		
		double ans = 0;
		
		Collections.sort(n1,Collections.reverseOrder());
		
		for (int i = 0; i < N-1; i++) {
            double d = n1.get(i);
			
			for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			}
			ans +=d ;
          
		}
		
		double d2 = n1.get(N-1);
		
		for ( int j = 0 ; j < N-1 ; j++)
			{
			d2 = d2 / 2;
			}
			ans += d2;
			
			System.out.println(ans);
	}
}
		
		 import java.util.*; util.* java import java.math.*; math.* java public class Main {
	
	public static void main(String[] args){
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

	    List<Double> n1 = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            double d = (double)sc.nextInt();
			n1.add(d);
		}
		
		double ans = 0;
		
		Collections.sort(n1,Collections.reverseOrder());
		
		for (int i = 0; i < N-1; i++) {
            double d = n1.get(i);
			
			for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			}
			ans +=d ;
          
		}
		
		double d2 = n1.get(N-1);
		
		for ( int j = 0 ; j < N-1 ; j++)
			{
			d2 = d2 / 2;
			}
			ans += d2;
			
			System.out.println(ans);
	}
} Main public static void main(String[] args){
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

	    List<Double> n1 = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            double d = (double)sc.nextInt();
			n1.add(d);
		}
		
		double ans = 0;
		
		Collections.sort(n1,Collections.reverseOrder());
		
		for (int i = 0; i < N-1; i++) {
            double d = n1.get(i);
			
			for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			}
			ans +=d ;
          
		}
		
		double d2 = n1.get(N-1);
		
		for ( int j = 0 ; j < N-1 ; j++)
			{
			d2 = d2 / 2;
			}
			ans += d2;
			
			System.out.println(ans);
	} main {
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

	    List<Double> n1 = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            double d = (double)sc.nextInt();
			n1.add(d);
		}
		
		double ans = 0;
		
		Collections.sort(n1,Collections.reverseOrder());
		
		for (int i = 0; i < N-1; i++) {
            double d = n1.get(i);
			
			for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			}
			ans +=d ;
          
		}
		
		double d2 = n1.get(N-1);
		
		for ( int j = 0 ; j < N-1 ; j++)
			{
			d2 = d2 / 2;
			}
			ans += d2;
			
			System.out.println(ans);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc List<Double> n1 = new ArrayList<>(); n1 new ArrayList<>() for (int i = 0; i < N; i++) {
            double d = (double)sc.nextInt();
			n1.add(d);
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            double d = (double)sc.nextInt();
			n1.add(d);
		} {
            double d = (double)sc.nextInt();
			n1.add(d);
		} double d = (double)sc.nextInt(); d (double)sc.nextInt() sc.nextInt sc n1.add(d) n1.add n1 d double ans = 0; ans 0 Collections.sort(n1,Collections.reverseOrder()) Collections.sort Collections n1 Collections.reverseOrder() Collections.reverseOrder Collections for (int i = 0; i < N-1; i++) {
            double d = n1.get(i);
			
			for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			}
			ans +=d ;
          
		} int i = 0; int i = 0; i 0 i < N-1 i N-1 N 1 i++ i++ i {
            double d = n1.get(i);
			
			for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			}
			ans +=d ;
          
		} {
            double d = n1.get(i);
			
			for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			}
			ans +=d ;
          
		} double d = n1.get(i); d n1.get(i) n1.get n1 i for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			} int j = 0 ; int j = 0 ; j 0 j < i + 1 j i + 1 i 1 j++ j++ j {
			d = d / 2;
			} {
			d = d / 2;
			} d = d / 2 d d / 2 d 2 ans +=d ans d double d2 = n1.get(N-1); d2 n1.get(N-1) n1.get n1 N-1 N 1 for ( int j = 0 ; j < N-1 ; j++)
			{
			d2 = d2 / 2;
			} int j = 0 ; int j = 0 ; j 0 j < N-1 j N-1 N 1 j++ j++ j {
			d2 = d2 / 2;
			} {
			d2 = d2 / 2;
			} d2 = d2 / 2 d2 d2 / 2 d2 2 ans += d2 ans d2 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 N = sc.nextInt();

	    List<Double> n1 = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            double d = (double)sc.nextInt();
			n1.add(d);
		}
		
		double ans = 0;
		
		Collections.sort(n1,Collections.reverseOrder());
		
		for (int i = 0; i < N-1; i++) {
            double d = n1.get(i);
			
			for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			}
			ans +=d ;
          
		}
		
		double d2 = n1.get(N-1);
		
		for ( int j = 0 ; j < N-1 ; j++)
			{
			d2 = d2 / 2;
			}
			ans += d2;
			
			System.out.println(ans);
	}
} public class Main {
	
	public static void main(String[] args){
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

	    List<Double> n1 = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            double d = (double)sc.nextInt();
			n1.add(d);
		}
		
		double ans = 0;
		
		Collections.sort(n1,Collections.reverseOrder());
		
		for (int i = 0; i < N-1; i++) {
            double d = n1.get(i);
			
			for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			}
			ans +=d ;
          
		}
		
		double d2 = n1.get(N-1);
		
		for ( int j = 0 ; j < N-1 ; j++)
			{
			d2 = d2 / 2;
			}
			ans += d2;
			
			System.out.println(ans);
	}
} Main

import java.util.*;
import java.math.*;
public class Main {
	
	public static void main(String[] args){
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

	    List<Double> n1 = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            double d = (double)sc.nextInt();
			n1.add(d);
		}
		
		double ans = 0;
		
		Collections.sort(n1,Collections.reverseOrder());
		
		for (int i = 0; i < N-1; i++) {
            double d = n1.get(i);
			
			for ( int j = 0 ; j < i + 1 ; j++)
			{
			d = d / 2;
			}
			ans +=d ;
          
		}
		
		double d2 = n1.get(N-1);
		
		for ( int j = 0 ; j < N-1 ; j++)
			{
			d2 = d2 / 2;
			}
			ans += d2;
			
			System.out.println(ans);
	}
}
		
		