Double_sided_arrow

<pattern_problem>

PATTERN DOUBLESIDED ARROW This program takes N as an input. For example, for a value of N = 7, we wish the program to draw the following pattern :

                        1 
                    2 1   1 2 
                3 2 1       1 2 3 
            4 3 2 1           1 2 3 4 
                3 2 1       1 2 3 
                    2 1   1 2 
                        1 

Input Format: We'll take N as input.

Constraints: N is odd number.

Output Format Pattern should be printed with a space between every two values.

Sample Input 7 Sample Output 1 2 1 1 2 3 2 1 1 2 3 4 3 2 1 1 2 3 4 3 2 1 1 2 3 2 1 1 2 1 End.