[PATCH -perfbook 5/5] intro: Say \co{-1} for constant -1

Signed-off-by: Akira Yokosawa <[email protected]>
---
 intro/intro.tex | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/intro/intro.tex b/intro/intro.tex
index fc0f97e2..4d51a965 100644
--- a/intro/intro.tex
+++ b/intro/intro.tex
@@ -1207,7 +1207,7 @@ struct htab *hash_lookup(int key);
 \end{VerbatimU}
 
 Here, \co{hash_add()} and \co{hash_del()} both return the exact number
-of elements in the hash table after the operation completes, or -1
+of elements in the hash table after the operation completes, or \co{-1}
 if the operation fails due to duplicate key or non-existent key,
 respectively.
 The \co{hash_lookup()} function takes a key and returns a pointer to
-- 
2.43.0