{"id":"max69-single-expression","text":"The entire solution is a single return expression (`int(str(num).replace(\"6\", \"9\", 1))`) with no control flow, leveraging `str.replace` count parameter for the \"at most one change\" constraint.","truth_value":"IN","source":"entries/2026/06/06/maximum-69-number-solution.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"max69-single-expression","truth_value":"IN","reason":"premise"}]}}