You have array a that contains all integers from 1 to n twice. You can arbitrary permute any numbers in a.

Let number i be in positions xi, yi (xi < yi) in the permuted array a. Let's define the value di = yi - xi — the distance between the positions of the number i. Permute the numbers in array a to minimize the value of the sum <image>.

Input

The only line contains integer n (1 ≤ n ≤ 5·105).

Output

Print 2n integers — the permuted array a that minimizes the value of the sum s.

Examples

Input

2


Output

1 1 2 2


Input

1


Output

1 1
import java.io.*;
import java.util.*;

public class optimal_permutation 
{
	
	
	public static void main(String args[]) throws IOException
	{
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int [] a = new int [2*n];
		
		int k = 0;
		int j = n;
		for (int i =  1; i < n; i++)
		{
			if (i % 2 != 0)
			{
				a[k] = i;
				a[n-i+k] = i;
				k++;
			}
			else
			{
				a[j] = i;
				a[j+n-i] = i;
				j++;
			}
			
		}
		
		for (int i = 0; i<2*n;i++)
			{
				if (a[i] == 0)
					a[i] = n;
			}
		StringBuilder ans = new StringBuilder();
		for (int i = 0; i<2*n;i++)
		{
			if (i > 0)	ans.append(" ");
			ans.append(a[i]);
		}
		System.out.println(ans.toString().trim());
		
	}

}
