aka na n da tte aka
aka na n da tte aka .
a k a WORD_BOUNDARY n a WORD_BOUNDARY n WORD_BOUNDARY d a WORD_BOUNDARY t t e WORD_BOUNDARY a k a WORD_BOUNDARY
a k a WORD_BOUNDARY n a WORD_BOUNDARY n WORD_BOUNDARY d a WORD_BOUNDARY t t e WORD_BOUNDARY a k a WORD_BOUNDARY