D. Number of Binominal Coefficientstime limit per test4 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputFor a given prime integer p and integers α, A calculate the number of pairs of integers (n, k), such that 0 ≤ k ≤ n ≤ A and  is divisible by pα. As the answer can be rather large, print the remainder of the answer moduly 109 + 7.Let us remind you that  is the number of ways k objects can be chosen from the set of n objects.InputThe first line contains two integers, p and α (1 ≤ p, α ≤ 109, p is prime). The second line contains the decimal record of integer A (0 ≤ A < 101000) without leading zeroes.OutputIn the single line print the answer to the problem.ExamplesInput2 27Output3Input3 19Output17Input3 39Output0Input2 45000Output8576851NoteIn the first sample three binominal coefficients divisible by 4 are ,  and .
Input2 27
Output3
['dp', 'math', 'number theory', '*3300']