huruf A bukan warna A
huruf a bukan warna a .
h u r u f WORD_BOUNDARY a WORD_BOUNDARY b u k a n WORD_BOUNDARY w a r n a WORD_BOUNDARY a WORD_BOUNDARY
h u r u f WORD_BOUNDARY a WORD_BOUNDARY b u k a n WORD_BOUNDARY w a r n a WORD_BOUNDARY a WORD_BOUNDARY . WORD_BOUNDARY