1 files changed, 3 insertions, 3 deletions

diff --git a/src/Codec/Wavefront/Token.hs b/src/Codec/Wavefront/Token.hs
index 01acd5c..70b3437 100644
--- a/src/Codec/Wavefront/Token.hs
+++ b/src/Codec/Wavefront/Token.hs
@@ -169,13 +169,13 @@ face = do
   where
     parseFaceIndices = fmap (\(i,k,j) -> FaceIndex i k j) parseFaceTriple `sepBy1` skipHSpace
     parseFaceTriple = do
-      v <- decimal
+      v <- signed decimal
       slashThenElse (parseVT v) (pure (v,Nothing,Nothing))
     parseVT v = slashThenElse (parseVN v Nothing) $ do
-      vt <- decimal
+      vt <- signed decimal
       slashThenElse (parseVN v $ Just vt) (pure (v,Just vt,Nothing))
     parseVN v vt = do
-      vn <- decimal
+      vn <- signed decimal
       pure (v,vt,Just vn)
 
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