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:
['1801', 'q', '5101', '8863', '2309', 'p', '8789', '9529', '6135', '5523', 'f', '8889', '7639', 'k', '263', '5751', '5529', 'g', '1451', '4143', 'e', '6987']

Ex Output:
e, f, g, k, p, q


Ex Input:
['3995', 'n', 'z', '8389', '7857', '3005', 'i', 'e', '1117', 'z', '8251', 'r', 't']

Ex Output:
e, i, n, r, t, z


Ex Input:
['w', '463', '4801', '1017', '4247', '7051', 'm', 'g', '3827', '9961', 'z']

Ex Output:

g, m, w, z