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:
['s', '2507', '3091', 'g', '7643', '2573', 'w', 'r', '1977', 'q', 'c', 'j', '1335', '9671', '7317', '567', '2041', '5777', 'w', 'm']

Ex Output:
c, g, j, m, q, r, s, w


Ex Input:
['o', '4167', 'b', '1651', '8327', '9219', 'o', 'v', '5841', '6057', 'i', 'q', 'o', 'r', 'a', '7069', 'y', 'h', 'd', '3775', 'j', 't', '3663', '55', '7117', 'e', 'u', 'm', '931', '5777', '8773', '4891']

Ex Output:
a, b, d, e, h, i, j, m, o, q, r, t, u, v, y


Ex Input:
['4825', '1815', 't', 'd', '207', '3223', '5841', 'q', '9635', '437', '2121', '8103', '473', '6353', 'j', '8007', '8799']

Ex Output:

d, j, q, t