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.
--------
Question: ['2409', 'q', 'w', 'e', 'x', '4737', 'w']

Answer: e, q, w, x


Question: ['6643', '6757', 'h', '1033', 's', 'c', '2003', 'p', '5483', 'f']

Answer: c, f, h, p, s


Question: ['e', '7525', 'd', '7859', 'e', '7453', 'a', '2363', 'p', '2519', '2639', '3821', 'b', '1687', '2001', '1831', 't', '4569', '3163', '8317', '4655', 'y', 'k', '7333', '7937', 'e', 's', 'x', 'y', '2387', '9457', '957']

Answer:
a, b, d, e, k, p, s, t, x, y