diff --git a/bin/day2403.ml b/bin/day2403.ml
index 531de90..cf2bcbe 100644
--- a/bin/day2403.ml
+++ b/bin/day2403.ml
@@ -1,7 +1,11 @@
-type cmd = Do | Donot | Mul of int * int
+(** Type containing commands available in input *)
+type cmd =
+  | Do  (** Enable processing *)
+  | Donot  (** Disable processing *)
+  | Mul of int * int  (** Multiply two integers. *)
 
 (** [find_nums s] returns the list of instructions given in [s]. *)
-let instrs_of_string s =
+let cmds_of_string s =
   let r =
     Str.regexp
       {|do()\|don't()\|mul(\([0-9][0-9]?[0-9]?\),\([0-9][0-9]?[0-9]?\))|}
@@ -23,8 +27,8 @@ let instrs_of_string s =
   in
   List.rev (impl [] 0)
 
-let instrs_of_file fname =
-  Aoc.strings_of_file fname |> List.map instrs_of_string |> List.concat
+let cmds_of_file fname =
+  Aoc.strings_of_file fname |> List.map cmds_of_string |> List.concat
 
 (** [mac acc a b] returns [acc + a * b]. *)
 let mac acc = function Mul (a, b) -> acc + (a * b) | _ -> acc
@@ -42,5 +46,4 @@ let day2403b lst =
   impl 0 true lst
 
 let _ =
-  Aoc.main instrs_of_file
-    [ (string_of_int, day2403a); (string_of_int, day2403b) ]
+  Aoc.main cmds_of_file [ (string_of_int, day2403a); (string_of_int, day2403b) ]