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:
['2349', 'p', 'a', '435', 'y', 'h', '3249', 'o']

Ex Output:
a, h, o, p, y


Ex Input:
['7123', 'm', 'h', '4065', 'c', 'n', '187', '3899', 'r', 'k', '2071', '9481', '6277']

Ex Output:
c, h, k, m, n, r


Ex Input:
['x', '151', '9761', 'e', '3187', 'i', '5209', '7977', 'b', '4855', 'i', 'c', '1669', 'l', '2361', '1367', '5293', 'a', '5205', 'z', '245', 'x', '6303', '4361', 'x', 'u', '4781', 'g']

Ex Output:

a, b, c, e, g, i, l, u, x, z