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: ['6709', 't', 'n', 'k', '991', 'a', '8899', '3563', '527', 'm', '4599', '6679', 'm', 'x', 'f', 'o', '3275', 'x', '677', 'b', '3329', '3593', '5183', '5753', 'u', '6045', '2607', 'y', '9873']

A: a, b, f, k, m, n, o, t, u, x, y
****
Q: ['4031', 't', 'o', 'c', 'x', '3007', '8329', '6345', '1267', '1017', 'o', 'x', 'l', '4129', 'd', '1987', '487', 'o', 'g', 'j', 'v', 'x', '3983', 'f', 'g', '5759', 'k', 'i', 'o', 'b', 'n', '683', 'j', 'o', 't', '4361', 'u']

A: b, c, d, f, g, i, j, k, l, n, o, t, u, v, x
****
Q: ['i', 'j', 'e', '8609', 'e', '245', '4553', 'k', 'e', '1703', 'r', '3053', 'v', '8275', 'd', 'a', 'd', 'c', 'u', '583', '3919', '5981', 'o', 'r', 'b', 'b', 'a', '3519', 'l', 'w']

A:
a, b, c, d, e, i, j, k, l, o, r, u, v, w
****