Phrasing confirmation on an algorithm

Hello all,

An task in one of my homework questions has a phrasing that's throwing me for a bit of a loop. I wanted to try and confirm it here.

The description of task is: Given n open intervals (a1, b1), (a2, b2), . . . , (an, bn) on the real line, each representing start and end times of some activity requiring the same resource, the task is to find the largest number of these intervals so that no two of them overlap.

I made up the following example intervals to demonstrate my point

* A (2,4)

* B (5,6)

* C (7,9) (Part of an overlap with D and E)

* D (8,11) (Part of an overlap with C and E)

* E (10,13) (Part of an overlap with C and D)

* F (14,16)

* G (18,20)

* H (22,24)

* I (24,29)

My understanding of the phrasing is that a function made to do this task using the above points would return a value of 4 (representing the non-overlapping chain of F,G,H,I). Does this seem proper?