diff --git a/vacuum_gambit.p8 b/vacuum_gambit.p8
index d923a5d..26863e9 100644
--- a/vacuum_gambit.p8
+++ b/vacuum_gambit.p8
@@ -191,7 +191,8 @@ end
 function ones(n)
  local ret = 0
  while n != 0 do
-  ret += 1
+  if (n&0x0.0001) ret += 1
+  n >>= 1
  end
  return ret
 end