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:
['3743', '765', '5299', '3069', '8547', '8991', '1811', 'k', '5557', '4907', '5907', 'd', 'r', 'z', '5385', '5463', 'f', '2063', 'm', '3419', 'k', '3897', '4049']

Ex Output:
d, f, k, m, r, z


Ex Input:
['l', '6313', '3199', 'w', '249', '8747', '7391', '3871', '173', 'x', 'o', '8647', '4413', '3645', '6123', '701', 'q', '2147', '4289', '7333', '533']

Ex Output:
l, o, q, w, x


Ex Input:
['5785', 'g', '1957', '9177', 'k', '7053', '4093', 'z', 'y', 's', '7253', 'n', '9553', 'n', '9085', '5739', '327', 't', '8861', '2511', '5281', '5339', 't', '2035', 's', 'b']

Ex Output:

b, g, k, n, s, t, y, z