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]: ['h', 'l', 'i', '1507', 'h', '409', '6777', 'u', '5563', '6113', '6513', '9949', '461', 'z', 'm', '2519', 'r', '4699', 'n', 'x', '4645']
[A]: h, i, l, m, n, r, u, x, z


[Q]: ['i', 'x', 'n', 'w', '8915', 'd', 'd', 'd', '6025', '7861']
[A]: d, i, n, w, x


[Q]: ['4487', 'h', 't', 's', 'e', 'f', 'g', 'y', 'a', '2279', '9789', '1937', 'p', '3875', 'p', 'x', 'g', '4139', '5287', 'c', '9821', '8573', 'l', 'o']
[A]:
a, c, e, f, g, h, l, o, p, s, t, x, y