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: ['5011', 'l', '925', 'e', 'b', '3077', 'm', '4541', '781']

Answer: b, e, l, m


Question: ['7155', 'y', '145', '7147', 'u', '8453', 'd', '3693', '6471', '5289', 'n', 'p', '8289', '2929', '199', 'e', '8377', '8937', '5315', 't', 'l', '7715', 'c', 'y', 'f', '9999', 'p', '3655', '5489', 'q', '2321', '9881', '2265', 'n', 'v', '455']

Answer: c, d, e, f, l, n, p, q, t, u, v, y


Question: ['z', 'k', '3675', 'h', '721', 'h', 'o', '4533']

Answer:
h, k, o, z