brr pan pan pan pan
brr pan pan pan pan
on n n n n
brr pan pan pan pan .
β r WORD_BOUNDARY p a n WORD_BOUNDARY p a n WORD_BOUNDARY p a n WORD_BOUNDARY p a n WORD_BOUNDARY
b r r WORD_BOUNDARY p a n WORD_BOUNDARY p a n WORD_BOUNDARY p a n WORD_BOUNDARY p a n WORD_BOUNDARY . WORD_BOUNDARY