DSA Week 1

How Many?

Time limit 1 second
Memory limit 128 MiB

Once preparing for the exam, Peter put in front of him n different cheating papers of his "favorite" subject "Calculus". And as during the semester Peter did not learn properly, there were so many cribs that they all can not fit into any pocket. Peter then found the maximum number of cribs, that he can take with him to the exam, and suddenly thought: how many ways are there to choose the right number of cribs?

Input data

Contains the total number of cribs n\:(1 \le n \le 12) and the number of cribs k\:(0 \le k \le n) that Peter can take with him.

Output data

Print the number of ways to choose k cribs from n.


Input example #1
3 2
Output example #1
Input example #2
4 1
Output example #2
Source 2012 All-Ukrainian Collegiate Programming Contest Round I Training Contest, April 19