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: ['6143', 'y', '5505', '9813', 'r', 'v', 'u', '8681', '2387', 'u', 'o', 'm', '9793', 'm']

A: m, o, r, u, v, y
****
Q: ['231', 'r', '5673', 'j', '589', 'z', '4659', 'a', '3763']

A: a, j, r, z
****
Q: ['4423', '5463', '8051', '3279', '1585', '7487', '6089', '5263', '1903', 'p', '7193', '3769', 'm', '6089', 'q', 'p', 'q', 'k', 'e', 'z', '7921', 'r', 't', 'd', '3557', 'z', 's', '435', 'g', '691', 'g', 'q', '8977', '9045', 'c', '2471', 'f', 'j', 'q', '7179']

A:
c, d, e, f, g, j, k, m, p, q, r, s, t, z
****