Mega Cool Numbers
A positive integer is called a cool number of power a if it can be separated into exactly a groups of consecutive digits, where the digits in each group form an arithmetic progression. An arithmetic progression is a sequence of numbers in which the difference between any two consecutive numbers is the same. A positive integer is called a mega cool number of power a if it is a cool number of power a, not a cool number of power a-1, and all its digits are in non-decreasing order.
Determine the number of mega cool numbers of power a that contain exactly n digits (with no leading zeroes). Print this number modulo 1000000007.
Input
Each line contains two integers n and a (1 ≤ n, a ≤ 1000).
Output
For each line of input print in a separate line the number of mega cool numbers of power a that contain exactly n digits (with no leading zeroes). The output numbers must be printed modulo 1000000007.