diff --git a/src/SM.ml b/src/SM.ml
index 98b00a9ba..5521f6ec5 100644
--- a/src/SM.ml
+++ b/src/SM.ml
@@ -41,7 +41,7 @@ let rec eval ((stack, ((st, i, o) as c)) as conf) = function
 
      val run : prg -> int list -> int list
 
-   Takes an input stream, a program, and returns an output stream this program calculates
+   Takes a program, an input stream, and returns an output stream this program calculates
 *)
 let run p i = let (_, (_, _, o)) = eval ([], (Expr.empty, i, [])) p in o