In this task, you are given an input list A comprising of numbers and alphabets. You need to extract and sort the unique alphabets in the list. The alphabets in the input list will only be in lowercase. Return -1 if there is no alphabet in the input list.

Ex Input:
['k', 'v', 'e', '6377', 'y', '3585', '4535', 'f', 'g', 'm', 'f', '8369', 'v', '7445', '4527', '9383', 'n']

Ex Output:
e, f, g, k, m, n, v, y


Ex Input:
['749', 'r', 'a', 's', 't', '5905', 'm', 'd', '8437', '4583']

Ex Output:
a, d, m, r, s, t


Ex Input:
['n', '6839', 'y', 'p', 'a', 'v', 'd', 'a', 'e', 'p', 'e', '1485', 'd', 'c', '5919', '1717', 'q', 'c', 'b', 'c', 'n', 'c', '5683', '1577', 'v', 'p', 'f', 'p', '2223', '8213', 'd', '605', '5331', 's', 'e']

Ex Output:

a, b, c, d, e, f, n, p, q, s, v, y