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: ['n', 'w', '6735', '3427', '6115', 'q', '7851', '3645', 'g', '6825', '6515', '4885', 'z']

A: g, n, q, w, z
****
Q: ['231', 'r', '5673', 'j', '589', 'z', '4659', 'a', '3763']

A: a, j, r, z
****
Q: ['i', '9981', '9235', '7189', '4447', 'd', 'u', 'c', 'w', '6517', 'e', 'a', 'h', '6773', 'v', 'v', '5811', '2667', 'i', 'o', '6859', '527', '7143', '4267', '905', 'o', 'a']

A:
a, c, d, e, h, i, o, u, v, w
****