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:
['a', 'p', 'y', 'l', 'l']

Ex Output:
a, l, p, y


Ex Input:
['g', 'u', 'q', '1375', '9491', 't', 'w', 'c', 'v', 'y', '3169', '1607']

Ex Output:
c, g, q, t, u, v, w, y


Ex Input:
['831', 'k', '1943', 'c', '1657', '4479', '6335', 'c', 'b', 'f', 's', 't', 'h', 'e', '9053', '1547', '7589', '7285', 'b', '3941', 'x', '8839', 'o', 'i', '2409', '5881', '8805', '5011', '4709', '6101', 'e', '7861', '4705', '2541', '2475', 'm', '395', 'z', 'l', '5993', 'w', 'g']

Ex Output:

b, c, e, f, g, h, i, k, l, m, o, s, t, w, x, z