-type t\r
-val magic: string list -> string list -> t\r
-val magic_conv: div:(string option) -> conv:string list -> nums:string list -> string list -> t\r
-val main: t list -> unit\r
+type problem\r
+val problem_of: div:(string option) -> conv:string list -> nums:string list -> problem\r
+val solve: problem -> unit\r
+val should_fail: (unit -> problem) -> unit\r