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]: ['8815', 'w', '8629', 'y', '3891']
[EX A]: w, y

[EX Q]: ['6027', 'v', 'b', 'l', '7853', 'r', 'y', '2919', '3831']
[EX A]: b, l, r, v, y

[EX Q]: ['5029', 'w', 'v', 'x', 'd', '1645', 'e', 't', '5243', '3685', '7155', '5357', '735', 'j', '5139', '4405', 'j', 'l', '8647', 'q', '9221', 'c', 'p', '1145', '6767', 'z', '9677', 'u', 'r', 'k', 'j', 'k']
[EX A]:
c, d, e, j, k, l, p, q, r, t, u, v, w, x, z