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:
['2181', '7019', 'l', 'z', 'z', 'y', '1245', '4179', '6951', '7249', '2723']

Ex Output:
l, y, z


Ex Input:
['2819', 'k', 'u', 'a', '4575', 'a', 't', 'a', 'f', '1507', '415', 'w', 'o', 'o']

Ex Output:
a, f, k, o, t, u, w


Ex Input:
['7689', '5809', '9057', 'm', 's', 'a', 'w', '7525', 'z', 't', '8451', '1767', 'b', 'g', 'o', 'l', 'k', '9189', '1321', '6689', '9783', 't', '2689', '7715']

Ex Output:

a, b, g, k, l, m, o, s, t, w, z