622_D. Optimal Number Permutation
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
```python
n = int(input())
A = [i for i in range(1, n+1, 2)]
B = [i for i in range(n-2 if n%2 else n-1, 0, -2)]
C = [i for i in range(2, n+1, 2)]
D = [i for i in range(n-1 if n%2 else n-2, 0, -2)]
ans = ' '.join(map(str, A+B+C+D+[n]))
print(ans)

```