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]: ['o', 'l', 'm', 't', '4487', '1019', '9903', 'c']
[A]: c, l, m, o, t


[Q]: ['s', 's', '3619', '6051', 'h', '213', '3937', 'v', 'p', 'y', '8449', '9337', '5327', 'a', 'a', 'w', '3985', 'n', 'm']
[A]: a, h, m, n, p, s, v, w, y


[Q]: ['j', 'm', 'u', 'g', '2045', '6729', 's', '7213', 'x', '4297', '9311', 'k', 'o', 'w', '199', 'w', 'b']
[A]:
b, g, j, k, m, o, s, u, w, x