Challenge

In this task you have compute the number of ways we can distribute A balls into B cells with with every cell having at-least one ball.

The inputs A and B are given in a single line separated by a blank,the inputs are terminated by EOF.

You may like to check your solutions here.

Input

12 4
6 3
18 17
20 19
15 13
18 9
20 20
17 14
9 2
14 13
18 11

Output

14676024
540
54420176498688000
23112569077678080000
28332944640000
38528927611574400
2432902008176640000
21785854970880000
510
566658892800
334942064711654400

Constraints

• Every A and B can be distinguishable.
• 0 <= A,B <= 20
• You can use any language of your choice
• Shortest solution wins!