Index: pyyaml/trunk/lib/yaml/resolver.py
===================================================================
--- pyyaml/trunk/lib/yaml/resolver.py	(revision 223)
+++ pyyaml/trunk/lib/yaml/resolver.py	(revision 226)
@@ -154,5 +154,5 @@
 Resolver.add_implicit_resolver(
         u'tag:yaml.org,2002:bool',
-        re.compile(ur'''^(?:yes|Yes|YES|n|N|no|No|NO
+        re.compile(ur'''^(?:yes|Yes|YES|no|No|NO
                     |true|True|TRUE|false|False|FALSE
                     |on|On|ON|off|Off|OFF)$''', re.X),