Determine the correctness of the following Assertion (A) and Reason (R) based on the Paniniya Shiksha:
Assertion (A): According to Shambhu (Panini), the number of letters in the Sanskrit alphabet is sixty-three or sixty-four.
Reason (R): According to the Paniniya Shiksha, the letter 'L' (L-kara) is dental (Dantya).