[It's highly likely his notebook is overpriced due to the rarity of paper in this world. He simply smiles as he sees him taking notes. For Mu, he didn't mind exchanging notes. But Mu learns to input that in his tablet by typing words in.]

I noticed that when I'm in the library too. There aren't any paper books, though I keep looking for it. All I find are these tablets.

I suppose that's why they kept all plants in the botanical garden.

[OOC: This is my reference! It was recently updated.]