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]: ['3147', '9807', '5313', '6311', '737', '1555', '5803', '3437', '5665', '3973', 'o', 'f', '7871', '1721', '7833', '2933', 'b', 'b', 'n', 'm', 'k']
[A]: b, f, k, m, n, o


[Q]: ['y', 'i', '257', '3695', 's', '6717', '4817', '4117']
[A]: i, s, y


[Q]: ['3701', 'u', '119', 'r', 'f', 'w', '1643', '5009', 'g', '5847', '5821', '8375', 'h', '8573', '2449', '97', '3647', 'i', 'j', 'm', 'u', '7745', '3019', '7853', '8713', 'p', 'l', 'g', '9049', 'g', '7929', 'w', '1545', '9943', '4337']
[A]:
f, g, h, i, j, l, m, p, r, u, w