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: ['s', 'u']

A: s, u
****
Q: ['6209', 'x', 'j', 'w', '7965', '4905', '6297', '4291', '7183', 'a', 'l', '5267', 'r', '5935', 'a', '7865', 'h', 'p', '6117', 'a', 'y', 'y', 't', 'v', '7271', 'e', 'e', 'z', 'i', 'l', '4731', '2059', 'm', '5703', 'k', 'f', '8125', 'e', '7569', 'r', '2287', '593']

A: a, e, f, h, i, j, k, l, m, p, r, t, v, w, x, y, z
****
Q: ['c', '125', 'k', 'v', '9781', 'w', '2723', 'q', 'i', 'i', 'f', '4125', '3285', '7063', 'd', 'q', 'k', 'u']

A:
c, d, f, i, k, q, u, v, w
****