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: ['5163', 'n', 'j', '67', '3801', 'n', '7113', 'z', '579', '6885', '8921', 'v', '5481', '5507', 'k', '8403', 'c', '837', 'u', '6341', 'd', 'i', '497']

Answer: c, d, i, j, k, n, u, v, z


Question: ['e', 'z', '5199', 'x']

Answer: e, x, z


Question: ['7221', '2585', 'o', '8241', 'e', '9807', 'b', '9465', 'r', '3013', 'i', '8239', 'c', '2579', 'x', 'w', '7855', 'q', '7039', 'd', '9951', 'b', 'g', '1927', 'f', '6395', '8721', '1915', '6143', '2099', 'l', '6553', '4059', '8171', '9083', '9055', 'o', 'b', '389']

Answer:
b, c, d, e, f, g, i, l, o, q, r, w, x