Yes, you are absolutely right, AnomalousMonk, I copied and pasted part of the original code too hastily. This is still quite messy, even if it works.

I'll fix that for future reference immediately after my answer.

The other point is that I am not convinced by the algorithm and I suspect it is probably not really what the OP wants, I have trouble finding a use case that would really make sense out of that, but I do not know what the OP wants would really and we don't have enough information, at least not at this point, to be sure.

Thank you very much.