This problem is basically the same as Section 5.5's Example 11. The best way to find the solution is to enumerate all possible ways to distribute five indistinguishable objects into three indistinguishable boxes.
5,
4, 1
3, 2
3, 1, 1
2, 2, 1.
There are 5 ways.
--Mkorb 19:41, 24 September 2008 (UTC)