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: ['3395', '7471', 'n', '9537', '1255', '1997', '3085', '4863', '9797', '4275', 'k', 'f', '8973', '3939', 'p', 'q', '4977', '6231', '8745']

A: f, k, n, p, q
****
Q: ['6643', '6757', 'h', '1033', 's', 'c', '2003', 'p', '5483', 'f']

A: c, f, h, p, s
****
Q: ['h', '781', 'o', '1917', 'b', 's', 'j', 'i', '6519', '665', '7237', '2577', '2511', 'u', 'g', 'v', 'p', 'x', '3441', '563', '7857', 'c', '9579', '7461', '3871', 'r', 'j', '1163', 'u', 'd', 'n', '2075']

A:
b, c, d, g, h, i, j, n, o, p, r, s, u, v, x
****