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:
['1449', 'a', '6261', '303', '4651', 'n', 'u', '1595']

Ex Output:
a, n, u


Ex Input:
['2165', 'f', '5081', 's']

Ex Output:
f, s


Ex Input:
['i', '8487', '4701', 'n', '6577', 'k', '7789', '3825', '9395', 'u', '7793', 'c', '5855', '9315', '8675', 'p', 'k', 'y', '3785', 'v', '9947', 'q', 'y', '8589', 't', '7465', '4227']

Ex Output:

c, i, k, n, p, q, t, u, v, y