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]: ['p', '9641', '8515', '1207', 'd', 'j', '6617', '5529', 'g', 'a', 'o', 'f', 'y', '4993', '4643', '6087', 'n', '3177', 'y', '9471', '1229', '8211', '7079']
[EX A]: a, d, f, g, j, n, o, p, y

[EX Q]: ['3797', '6117', 'x']
[EX A]: x

[EX Q]: ['5131', '4695', '5537', 'j', 't', '7429', '2113', '3277', '9143', 'r', 'j', 'i', '8229', '9541', 'n', '5851', 't', '3159', 'b', '8867', '81', 'e', 't', 'n', 'z', '7021', 'w', 'a', '7213', 'd', 'f', '3273', 'x', 'd', '8643', 'u', '9757', '1533', '691', 'b', '3185', '4571']
[EX A]:
a, b, d, e, f, i, j, n, r, t, u, w, x, z