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]: ['7071', 'h', '837', 'z', 'c', '2217', 'c', '6341', '6607', 'g', '3569', 'a', 'h', 't', 'b', 'f', 'g', 'f', 'l', 'b', 'x', 'o', 'r', '8949', '8071', '1507', 'v']
[A]: a, b, c, f, g, h, l, o, r, t, v, x, z


[Q]: ['6769', 's', '3353', '4453']
[A]:
s