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: ['f', 'p', 'n', '839', '9229', 'r', '7661', 'c', '4383', 'u', 'k', '5321', '3181', '1785', 'w', 'k', '8721', '7855', '4093', '6495', 'q', '2467', 'g']

A: c, f, g, k, n, p, q, r, u, w
****
Q: ['6737', 'g', '9985', '5257', 'k', 't', '7863', 'y', '8319', 'l', 'o', '6505', '6531', 'z', '3055', '2943', '3625', 'h', '4867']

A: g, h, k, l, o, t, y, z
****
Q: ['8223', 'e', 'r', '1343', '8777', 'u', '1633', 'z', 'x', 'f', 'w', '9071', 'c', '5227', '4675', 'i', '3615', '1275', '891', 'h', '9679', 'w']

A:
c, e, f, h, i, r, u, w, x, z
****