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:
['6027', 'v', 'b', 'l', '7853', 'r', 'y', '2919', '3831']

Ex Output:
b, l, r, v, y


Ex Input:
['3561', 'd', '9697', 'd', '7761', 'a', '2833', 'c', '2921', 't', '691', 'g', '4797', 'b', '3913', 'f', 'q', '7807', 'j', '3577', 'j', '1775', '2897', '2589', '993', '8595']

Ex Output:
a, b, c, d, f, g, j, q, t


Ex Input:
['t', 'n', 'w', 'd', 'w', 'n', '7671', '4285', '4497']

Ex Output:

d, n, t, w