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: ['887', 'p', '3819', '2727', '1407', 'b', 'n', '737', 'd', 'w', 'q', '6877']

A: b, d, n, p, q, w
****
Q: ['n', 'y', '7087', '9539', 'x', 'i', 'w', '7237', '8613', 'k', '5999', '4179', 'o', 'm', '7485', '1955', 'w', '1451', 'h']

A: h, i, k, m, n, o, w, x, y
****
Q: ['x', '3989', 'u', 'e', '8415', '1393', '8681', 'b', '8207', '1529', 'f', '857', 'q', 'l', '2217', '5567', 'i', '4775', '1377', 'y', '7527', 'b', '9691', 'h', '1179', '2217', '3623', 'n', 'g', '5523', 'v']

A:
b, e, f, g, h, i, l, n, q, u, v, x, y
****