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: ['2313', '2073', 'd', 'e', 'o', '793', '4999', 'f', 'c', '4473', '4519', 'u', 'n', 'k', '69', '475', 'a', 'j', 'q', 'x', '5869', '9523', 'z', 'v', '9265', '5989', 'p', 'm', 'g', 'y', 'b']

Answer: a, b, c, d, e, f, g, j, k, m, n, o, p, q, u, v, x, y, z


Question: ['q', 'o', '1205', '4429', '6301', 'e', '2857', '5075', '5121', 'p', 'b', '5801', 'a', 'm', 'j', 'p', '1279', '7011', 'x', '2557', 'k', 'v', 'b', 'u', 'w', 'n', '1689', 'o', '1583', 'w', '6403', 'p', '6397', 'e', '823', '5699', 'd', '3399', 'd', 'b']

Answer: a, b, d, e, j, k, m, n, o, p, q, u, v, w, x


Question: ['7213', 'r', '1303', 'j', 'o', '1281', 'h', 'i', '6371', 's', 'm', 'w', 's', '9863', 'c', 'o', 'e', 's', 'f', '4961', 'b', '219', '9229', '3021', 'p', '1039', 'l', 'z', '375', 'h', 'x', '2845', 'c', 'k', '7707', '4735', 'v', 'y', 'w', 'b', 'u']

Answer:
b, c, e, f, h, i, j, k, l, m, o, p, r, s, u, v, w, x, y, z