AB33, thanks a lot for your help.
Really, I had no intention of offending you If you read my first post I said my wanted output should be
A 1
A 2
..
A 5
B 1
B 2
..
B 100
C 1
C 2
..
C 299

So, repeating the label until there was a different value for that. But eventually, I'm not English so my explanation might have not been as clear as I thought.

Thanks again for your help!