Description

Bessie taught the cows to make Parkside's Triangle. It is generated from two numbers: the size and the seed. The size N (1 <= N <= 20) determines how many rows are in the triangle and the seed S (1 <= S <= 9) determines the first number in the triangle. Here are two examples:

 N=5, S=3                  N=6, S=1  

3 4 6 9 4                1 2 4 7 2 7    
  5 7 1 5                  3 5 8 3 8    
    8 2 6                    6 9 4 9    
      3 7                      1 5 1   
        8                        6 2  
                                   3

The first line of any triangle has no blanks at its front.

Analyze the above examples, discover the rule, and write a program that will generate Parkside's Triangle given any size N (1 <= N <= 20) and any seed S (1 <= S <= 9).

Input

Line 1: Two space-separated integers: N and S

Output

Lines 1..N: Parkside's Triangle as above; no trailing blanks on any line.

5 3

3 4 6 9 4
  5 7 1 5
    8 2 6
      3 7
        8

Source

USACO 2006 December Bronze