The Candies#65
Ivanko loves candies. He has many candies and stores them in special boxes. Ivanko has candies (where is even) and identical boxes. No box can contain more than candies.
Ivanko wonders: how many different ways can he distribute all his candies into the boxes?
All candies are identical, so only the number of candies in each box matters. Two distributions are considered different if there is at least one box that contains a different number of candies.
The only line contains two integers and — the number of candies (2 \leq N \leq 1000, is even), and the number of boxes (2 \leq S \leq 1000).
Print a single integer — the number of different possible ways to distribute the candies into the boxes.
Example 1