diff --git a/CCard.hs b/CCard.hs
index ec94333..4aff7ff 100644
--- a/CCard.hs
+++ b/CCard.hs
@@ -1,7 +1,7 @@
 module CCard where
 
 import Data.Word (Word64)
-import Data.Bits (setBit, (.|.))
+import Data.Bits (setBit, (.|.), (.&.), shift, xor)
 
 newtype Card = Card Int
 type Pack = Word64
@@ -44,8 +44,17 @@ ribbons = set [14, 18, 26, 41] .|. blue .|. poetry
 lights :: Pack
 lights = set [3, 11, 31, 43, 47]
 
+lastIndex :: Int
+lastIndex = 47
+
+plain :: Pack
+plain = pack `xor` (lights .|. ribbons .|. animals) .&. pack
+
+pack :: Pack
+pack = 1 `shift` (lastIndex + 1) - 1
+
 pair :: Card -> Card -> Bool
 pair card1 card2 = flower card1 == flower card2
 
 cards :: [Card]
-cards = map Card [0..47]
+cards = map Card [0..lastIndex]