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.

Q: ['o', '9599']

A: o
****
Q: ['7367', '9757', '9431', 'h', 'a', 'k', '5833', '6237', 'g', '3585', '8665', 'g', '7517', '1561', 'p', 'p', '1307', '3325', 'q']

A: a, g, h, k, p, q
****
Q: ['5685', '9789', 'w', 'p', '2511', '941', 'j', '8307', '5197', 'z', '8253', '6701', '5225', '2701', 'y', '7673', '7651', 'e', 'g', '6069', 'm', 'b', '4931', 'i', 'v', '1041', 'v', '2169', 'b', '1997', '1401', '539']

A:
b, e, g, i, j, m, p, v, w, y, z
****