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:
['459', '1729', 'b', 'c', '9619', '4461', '4347', '6733', 'i', '3631', 's', 'j', 'i', 'r', '5293', 'q', '7397', '4309', 'c', 'n', 'k', '197', 'q', '8139']

Ex Output:
b, c, i, j, k, n, q, r, s


Ex Input:
['k', 'r', 'f', '4369', 'z', 'z', 'l', '143', 'r', '707', '9167', 'g', '1749', 'i']

Ex Output:
f, g, i, k, l, r, z


Ex Input:
['6973', '8727', '1831', '6437', 'o', 'f', '5457', '9387', '5201', '7619', 'm', '5767', 'r', 'h', 'y', 't', '4043', '2241', '579', '7747', '6915', 't', '5375', 'e', 't']

Ex Output:

e, f, h, m, o, r, t, y