"This is the 'Vse GDZ' compendium," the man said, sliding it across the wood. "It has the answers for every exercise from Brest to Vitebsk. But remember, boy—the solution manual tells you the 'what,' but it never explains the 'why.'"

On Monday morning, he sat in the exam hall. The sun hit his desk, illuminating the blank white paper. He looked at the first question—a problem involving the velocity of a train leaving Minsk-Passazhirsky.

The old man didn’t look up. "You mean the GDZ? The solutions? You know the teachers at Gymnasium No. 1 say those books are cursed. They say if you use them, you forget how to think."

The bookseller sighed and reached under the counter. He pulled out a stack of books bound in the familiar, austere style of the Narodnaia Asveta publishing house. The covers were clean, but the edges were softened by the frantic thumbs of a thousand students before him.

He closed his eyes, expecting the GDZ's perfect steps to appear in his mind. But all he saw were the shapes of the numbers, not the logic behind them. He realized the bookseller was right. He had the key to the door, but he had forgotten how to walk through it.

"I need it," Maxim whispered, glancing over his shoulder. "The complete set. Narodnaia Asveta editions. Everything for the 11th-grade finals."