0295. Binomial Showdown

Input file name:	binomial.in
Output file name:	binomial.out
Time limit:	2 s
Memory limit:	256 megabytes

In how many ways can you choose k elements out of n elements, not taking order into account?
Write a program to compute this number.

Input Specification

The input file will contain one or more test cases.
Each test case consists of one line containing two integers n (n>=1) and k (0<=k<=n).
Input is terminated by two zeroes for n and k.

Output Specification

For each test case, print one line containing the required number. This number will always fit into an integer, i.e. it will be less than 2³¹.

Warning: Don't underestimate the problem. The result will fit into an integer - but if all intermediate results arising during the computation will also fit into an integer depends on your algorithm. The test cases will go to the limit.

Sample Input

4 2
10 5
49 6
0 0

Sample Output

6
252
13983816

Source: Ulm University Local Contest 1997

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