Question
1. You are given a number n, representing the number of elements.
2. You are given a number k, representing the number of subsets.
3. You are required to print the number of ways in which these elements can be partitioned in k non-empty subsets.
E.g.
For n = 3 and k = 3 total ways is 6
12-3-4
1-23-4
13-2-4
14-2-3
1-24-3
1-2-34
Input Format
A number n
A number k
Output Format
A number representing the number of ways in which these elements can be partitioned in k non-empty subsets.
Constraints
0 <= n <= 20
0 <= k <= n
Sample Input
4
3
Sample Output
6