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]: ['9947', '3353', '8643', '4621', '4857', 'y', '7075', 'c', '8911']
[A]: c, y


[Q]: ['4123', '1397', '103', 'w', 't', 'j', '233', '7239', 'b', 'n', 't', '6273', 'l', '1167', '8389', '5609', '9029', '7741', 'o', 'p', '6547', '5593', 'd', '8401', 's', '4243', 's', 'u', 'm', '6659', '5691', '2105', '8897']
[A]: b, d, j, l, m, n, o, p, s, t, u, w


[Q]: ['8585', '5317', '3521', '7363', '149', 'i', '1589', 'u', '9543', 'j', '669', 'w', 'g', 's', '8773', 'w', 'v', 'a', '7', 'n', '4039', '3007', '5461', '9779', '8417', '3905', 'v', 'w', 'g', 'm', '6575', '671', '4019', '7371', '3405']
[A]:
a, g, i, j, m, n, s, u, v, w