diff --git a/gcd.ml b/gcd.ml
index 96708bf..c56284f 100644
--- a/gcd.ml
+++ b/gcd.ml
@@ -6,10 +6,10 @@ let rec gcd a b =
 let main () =
   let len = Array.length Sys.argv in
   Printf.printf "array length %d\n" len;
-  if len < 3 then (
+  if len < 3 then begin
     Printf.printf "must have 2 args";
     exit 0;
-  );
+  end;
   let a = int_of_string Sys.argv.(1) in
   let b = int_of_string Sys.argv.(2) in
   Printf.printf "gcd of %d and %d is %d\n" a b (gcd a b);