diff --git a/src/Data/Word/Adler32.hs b/src/Data/Word/Adler32.hs
--- a/src/Data/Word/Adler32.hs
+++ b/src/Data/Word/Adler32.hs
@@ -24,8 +24,8 @@
 
 data A = A !Word32 !Word32 deriving (Show, Eq)
 
-initial :: A
-initial = A 1 0
+initial :: (Int, A)
+initial = (5551, A 1 0)
 
 fromWord32 :: Word32 -> A
 fromWord32 w = A (w .&. 0xffff) (w `shiftR` 16)
diff --git a/tools-yj.cabal b/tools-yj.cabal
--- a/tools-yj.cabal
+++ b/tools-yj.cabal
@@ -5,7 +5,7 @@
 -- see: https://github.com/sol/hpack
 
 name:           tools-yj
-version:        0.1.0.37
+version:        0.1.0.38
 synopsis:       Tribial tools
 description:    Please see the README on GitHub at <https://github.com/YoshikuniJujo/tools-yj#readme>
 category:       Tools