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:
['u', 'd', '4193', '5687', 'p', 'r', '7787', 't']

Ex Output:
d, p, r, t, u


Ex Input:
['y', 'g', '107', '4899', '6357', '9777', 'k', '1865', '7029', 'q', 'x', '7051', 's', '6125', '4285', '2731', 'z', 'a', '737', '6137']

Ex Output:
a, g, k, q, s, x, y, z


Ex Input:
['w', 't', 'i', '1181', '4823', '2507', '859', 'h', '8497', '8607', '6617', '879', '9689', '5017', 'x', 'k', 'e', 'l', 'a', 'g', '2049', 'e', 'z', '4079', '8467', '4899', '7365', 'n', 'h', 'o', 'r']

Ex Output:

a, e, g, h, i, k, l, n, o, r, t, w, x, z