Challenge We're given secret. txt , a single line of comma-separated tuples wrapped in what looks like braces and underscores: (4, 17), (2, 16), (2, 15), (4, 9), { , (3, 2, 1), (5, 3), _ , (2, 17), ... $ file secret.
Source: [Dev.to](https://dev.to/exploitnotes/broncoctf-atomic-substitution-theory-writeup-1ckd)