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: ['3411', 'a', 'v', 'j', '8925', '909', 'h', 'l', 'r', '1371', 'u', '7789', '4813', 'u', 'q', 'i', '8473', 'n', '7191', 'c', '4641', 'e', '5107', 'q', 'z', 't', '105', 'q']

Answer: a, c, e, h, i, j, l, n, q, r, t, u, v, z


Question: ['6599', 'f', 'c', '661', 'q', 'e', '1951', 'f', 'f', 'a', 'd', '9521', '853', 'n', 'w', '6451', '5549', 'k', 't', 'l', 'z', 'm', 'k', '567']

Answer: a, c, d, e, f, k, l, m, n, q, t, w, z


Question: ['b', '2157', '7519', 'c', 'f', '8551', 'y', '8003', 'r', '3231', '1609', '8161', 'z', 'd', 'u', 'i', 'q', '8063', 'l', '3977', '7761', 't', '6993', '8631', 'i', '3941', '6313', '2467', 'b', '1421', 'h', '439', 't', '2699', 'w', 'u', 'o', 'x', 't', '7861', '9499', 'w']

Answer:
b, c, d, f, h, i, l, o, q, r, t, u, w, x, y, z