But if you went by and grabbed the very first sentence from each chapter that's is sufficiently in the clear. Especially when you are doing something transformative with it. Like for example analysing what makes for an effective opening sentence.
With copyright you always get to ugly slippery slope arguments, Tom Scott has a great video on it.
But if you cannot extract something the replaces the original work you should be already in the clear. I'm pretty sure Cole's Notes don't need the original author's permission to print and they are arguably a substitute for reading the original work. I've skimmed through entire series by reading the individual episode summaries on Wikipedia. These are in the clear.
The fact that a machine speeds up a human process does not change legality.
1. Anything existing is considered a fact.
2. Stating a fact doesn't infringe copyright.
The only conclusion your logic can infer to is copyright doesn't exist.
For example, I can say "the first sentence of A Song of Fire and Ice series is <insert the first sentence>, the second sentence is <insert the second sentence>, the third sentence is...". It's still just a list of facts, so no copyright infringement, right?