In the story "The Cask of Amontillado, Montressor had led Fortunato in a family of catacombs. He had led him to a pile of skeletons and chained Fortunato's arm. No one knows what happened to Fortunato at the end. All they know is that Fortunato disappeared, and no one ever saw him again.
20-8.
so 20 less than 8..
20,19,18,17,16,15,14,13,12. you stop.
12 is the answer