I need help to understand a homework

[SantiagoPB]

does this presentation help

Output:
1
1 --> 11
11 --> 21
2-1 --> 12-11
1-2-11 --> 11-12-21
111-22-1 --> 31-22-11
3-1-22-11 --> 13-11-22-21
... and so on

e.g. the last number in my example 13112221 describes the previous 312211, which consists of one 3, one 1, two 2, two 1, i.e. 13112221

Yes it is clear now, thank you a lot :D