diff --git a/interp/Makefile b/interp/Makefile
new file mode 100644
index 0000000..f90bf58
--- /dev/null
+++ b/interp/Makefile
@@ -0,0 +1,4 @@
+
+all:
+	ocamlc -o interp nums.cma interp.ml
+
diff --git a/interp/interp.ml b/interp/interp.ml
index f31408d..d994c8f 100644
--- a/interp/interp.ml
+++ b/interp/interp.ml
@@ -337,7 +337,8 @@ let step_star deck : string =
     st.pc |> lkup_instr deck
           |> step st
   done;
-  bigs_str st.out
+  st.out |> bigs_str
+         |> mkstr "%s\n"
 
 let main () =
   () |> input_deck