diff --git a/vacuum_gambit.p8 b/vacuum_gambit.p8
index adb2afc..497a720 100644
--- a/vacuum_gambit.p8
+++ b/vacuum_gambit.p8
@@ -193,6 +193,7 @@ function ones(n)
  while n != 0 do
   ret += 1
  end
+ return ret
 end
 
 function updategame()