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.

['1449', 'a', '6261', '303', '4651', 'n', 'u', '1595']
a, n, u

['n', 'h', 'j', '5945', '8511', 'y', '7739', '4717', '2483', 'p', '9545', '7647', '9863', '5591', '5393', 'i', '9225', '589', '1497', 'j', 'm', '2397', 'a', 'd']
a, d, h, i, j, m, n, p, y

['2233', '8755', 'w', '3113', '5315', 'f', '7079', 'h', '4513', '4625', 'x', 'c', 'x', '5419', '8857', '175', '8297', '3937']

c, f, h, w, x