apúpa apúpa aúpa abúpa
apúpa apúpa aúpa abúpa .
a p u p a WORD_BOUNDARY a p u p a WORD_BOUNDARY a u p a WORD_BOUNDARY a β u p a WORD_BOUNDARY
a p ú p a WORD_BOUNDARY a p ú p a WORD_BOUNDARY a ú p a WORD_BOUNDARY a b ú p a WORD_BOUNDARY . WORD_BOUNDARY