Given two integers ~N~ and ~M~, output ~\frac{N!}{M!}~.

Note that the notation ~K!~ represents the product of all integers ~1, 2, 3, \ldots, K~.

Input Specification

The first line will contain a single integer ~N~. ~N~ is guaranteed to be greater than or equal to ~1~ and less than or equal to ~15~.

The next line will contain a single integer ~M~. ~M~ is guaranteed to be greater than or equal to ~1~ and less than or equal to ~N~.

Output Specification

Output a single integer, the value of ~\frac{N!}{M!}~.

Sample Input 1

5
2

Sample Output 1

60

Sample Input 2

1
1

Sample Output 2

1