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]: ['t', 'x', '1699', '8727']
[A]: t, x


[Q]: ['3947', '4809', 'b', 'a', '4769', '4179', '535', '5965', 'f', 'j', '2265', 'w', '3103', 'u']
[A]: a, b, f, j, u, w


[Q]: ['q', 'v', '6279', 'd', '4951', '1085', '5461', '941', 'c', 'w', 't', '6119', '581', '2193', '4295', '2985', 'w', '6463', '4059', 'b', 'y', '445', 'b', '5693', '2099', '6399', 'b', 'i', 'a', 'j', '183', 'f', 'n']
[A]:
a, b, c, d, f, i, j, n, q, t, v, w, y