Divisors (求解组合数因子个数)【唯一分解定理】

Divisors

题目链接（点击）

Your task in this problem is to determine the number of divisors of Cnk. Just for fun -- or do you need any special reason for such a useful computation?

Input

The input consists of several instances. Each instance consists of a single line containing two integers n and k (0 ≤ k ≤ n ≤ 431), separated by a single space.

Output

For each instance, output a line containing exactly one integer -- the number of distinct divisors of Cnk. For the input instances, this number does not exceed 2 63 - 1.

Sample Input

5 1
6 3
10 4

Sample Output

2
6
16

思路：

之前用求逆元的方法可以将组合数的最终值求出来，但是这个题目并没有给出要mod的值，所以先将结果求出来然后用唯一分解定理求因子个