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:
['8527', 'p', '4697', '8415', 'v', 'l', '2669', '2649', '4349', '4201', 'r', '7573', '2041', 'f', '8047', 'u', 'm', 'm', 'j', '5695']

Ex Output:
f, j, l, m, p, r, u, v


Ex Input:
['a', '533', '67', 'z', 'z', '9283', 'o', 'a', '7045', '1521', 'm', 'h', 'q', '4173', '7497', '319', '5721', '6097', 'i', '9829', '1801', '7347', 'r', 'z', '239', '4279', 'e', 'k', 'r', 'v', '6653', '599', '8597', 'd', 'r']

Ex Output:
a, d, e, h, i, k, m, o, q, r, v, z


Ex Input:
['p', 'f', '1659', 'v', 'a', '8631', '1695', '9911', '3895', 'b', '7991', 'w', '9347']

Ex Output:

a, b, f, p, v, w