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:
['1595', '2915', 'o', 't', 'c', 'h', '3969', '5407']

Ex Output:
c, h, o, t


Ex Input:
['4993', 'n', '7115', 'f', 'd', 'q', '249', '3203', 'w', '5689', '4103', '7129', '603', 'e', 'z', '5571', '3241', '6029', '2721', '8451', 'o', '7841', 'p', '6271', 'r', 'b', '9481', '4045', 'v']

Ex Output:
b, d, e, f, n, o, p, q, r, v, w, z


Ex Input:
['b', 'e', 'u', '8429', 'd', 'l', '687', '8459', '1105', '1809', 'k', '4841', '9105', '7391', '507', '193', 'v', '1929', 'i', 'q', 'u', 'p', '7317', 'p', 't', 'o', '9081', 'n', '4467', '9773', 'b', '1391', '8413', '5253', 'i', 'q', 's', '7239', 'c', 'a', '1733']

Ex Output:

a, b, c, d, e, i, k, l, n, o, p, q, s, t, u, v