Why, nikāyas, of course! 
Nikāya Puritans would always acknowledge 5, but if you’re “truly” a “radical” Puritan (he said, with an eyebrow raised), you only acknowledge 3 nikāyā, namely Aṅguttara, Majjhima, and Saṁyutta.*
I don’t consider a Puritan a “good” thing to be necessarily, maybe that is an inadvertent exhibition of a Canadianism. If that’s so, in the above haiku, with the meaning I intended, I don’t think anyone should be a “purist” that way. Maybe it didn’t some across right when read. It’s certainly possible. It wouldn’t be the first time I had a hard time “explaining myself,” so to speak, in prose or poem. 
*That is to say, there is a movement in EBT subculture, chiefly prevalent on web forums thankfully unlike this one, that devalues the Dīgha & Khuddaka as authentic.