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: ['749', 'r', 'a', 's', 't', '5905', 'm', 'd', '8437', '4583']

A: a, d, m, r, s, t
****
Q: ['395', '8309', 'v', 'r', 'x', 'j', 'l', 'b', 'c', 'c', '3123', 't', 'a']

A: a, b, c, j, l, r, t, v, x
****
Q: ['s', '6841', 'm', 'l', 'v', 'a', 't', 'h', '9085', 'x', 'f', '5957', 'g', 'h', '1387', 'j', 'e', 'e', '4407', 'i', '3317', '3961', '4737', 'c', 'x', 'c']

A:
a, c, e, f, g, h, i, j, l, m, s, t, v, x
****