How does Max respond to Liesel's question about whether Mein Kampf is a good book?

Max doesn't respond.

Max, following her attention, also examined the book.
“Is?” she whispered.
There was a queer strand in her voice, planed off and curly in her mouth.
The Jew moved only his head a little closer. “Bitte? Excuse me?”
She handed him the pea soup and returned upstairs, red, rushed, and foolish.
“Is it a good book?”
She practiced what she’d wanted to say in the washroom, in the small mirror. The smell of urine was still about her, as Max had just used the paint can before she’d come down. So ein G’schtank, she thought. What a stink.