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: ['p', '9641', '8515', '1207', 'd', 'j', '6617', '5529', 'g', 'a', 'o', 'f', 'y', '4993', '4643', '6087', 'n', '3177', 'y', '9471', '1229', '8211', '7079']

A: a, d, f, g, j, n, o, p, y
****
Q: ['x', 'j', '9747', 'i', '2015', '3505', 'q', 'n', 'h', '3011', 'u', '8043', 'j', 'f', 'd', 'a', 'p', '5817', 'l', 'q', '2275', 'n', '7085', '5373', 'l', 'g', 'b', '8043', '3085']

A: a, b, d, f, g, h, i, j, l, n, p, q, u, x
****
Q: ['r', 'b', '3773', '2773', 'q', 'k', 'i', 'f', '7267', 'a', 'u', 'h', '1469', 's', '9319', 't', 'e', 'e', '13', '7697', 'g', 'a', 'e', 'w', '6779', '9517', 'z', 's', 't', 'j', 'u', 'p', 'm', 'b', 'h', '3189']

A:
a, b, e, f, g, h, i, j, k, m, p, q, r, s, t, u, w, z
****