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]: ['9689', '9727', 't', 'd', '2103', 'c', 'n', '8553', '4559', '7815', 'u', 'l', 'c', 'e', 'u', 'n', '7207', '4875', '7699', 'h']
[A]: c, d, e, h, l, n, t, u


[Q]: ['699', 'd', '6027', 'j', 'e', 'c', 't', '9983', '5471', '2649', 't', '2631', 'r', 'h', '293', 'j', '8699', 'p', 'k', '5433']
[A]: c, d, e, h, j, k, p, r, t


[Q]: ['9631', '7945', 'v', '5233', 'u', '5053', 'l', 'r', '1191', 'n', '7145', 'w', 'x', '9233', 'f', 'v', '3579', 'n', '3559', 'd', '2781', 'f', 'a', '1939', 'k', 'q', '8925', '2993', '7601', '6483', 'x', 'g', '139', 'v', '7193', '3391', '1397', '3217', '9949', '3505', 'n']
[A]:
a, d, f, g, k, l, n, q, r, u, v, w, x