For 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 $*p*^{α}$.
As the answer can be rather large, print the remainder of the answer moduly $10^{9} + 7$.
Let us remind you that
is the number of ways $*k*$ objects can be chosen from the set of $*n*$ objects.
Input
The first line contains two integers, $*p*$ and $α$ ($1 ≤ *p*, α ≤ 10^{9}$, $*p*$ is prime).
The second line contains the decimal record of integer $*A*$ ($0 ≤ *A* < 10^{1000}$) without leading zeroes.
Output
In the single line print the answer to the problem.
Note
In the first sample three binominal coefficients divisible by 4 are
,
and
.
样例
2 2
7
3
3 1
9
17
3 3
9
0
2 4
5000
8576851
题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。