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 Q]: ['8311', 'w', 'f', '3431', '9863', '5817', '3969', '2705', 'x', 'm', 'k', 'z', 'z', '235', 'x', '417', 's', 'i', 'y', '8833', '8675', 's', 'm', '2149', '765', 'u', '1021', '7823', 'x', '7275', '3157', 'k']
[EX A]: f, i, k, m, s, u, w, x, y, z

[EX Q]: ['3995', 'n', 'z', '8389', '7857', '3005', 'i', 'e', '1117', 'z', '8251', 'r', 't']
[EX A]: e, i, n, r, t, z

[EX Q]: ['7837', 'o', '5869', 'v', '4543', 'u', '5587', '7359', 'v', '6147', 'j', '2303', 'n', '313', '1887', 'k', '4493', '2537', 'a', '3701', '4661', 'r', '5039', '6991', '4441', 'n', '8359', '1589', '3813', 's', 'j', 'w', '5485', '435', '1623', '8037', '6127', '3727', '1371', '8185', 'y', 'b', '695', '1427']
[EX A]:
a, b, j, k, n, o, r, s, u, v, w, y