instruction:
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:
['4269', '1847', '2025', '601', 'g', 'n', 'h', '3499', '4977', '3579', '9355', '3489', 'm', 'm', '4401', '4605', 'l', '3977', 'h', 'd', 't', '5135', '7787', 'k', 'q', '7699', '5325', '6269', '1865', 'h', '8915', '5677', 'g', '603', '1435']
answer:
d, g, h, k, l, m, n, q, t


question:
['z', 'm', 'n', 'u', '9159', '7931', '5401', '1383', '8195', 't', 'x', 'q', 'r', '2535', 's', 'j', 'c', '8123', '2429', '5581', 'k', 'c', 't', 'i', 'm', 'o', 't', 'q', '4819', 't', '1649', 'r', 'y', 'z', '8813', '7451', '199', 'o', 'x', 's', 's', '6747']
answer:
c, i, j, k, m, n, o, q, r, s, t, u, x, y, z


question:
['7543', 'r', 'y', 'z', '789', 'w', 'd', '9929', '9153', '3291', '1197', 'y', 'd', '7563', '2393', 'b', 't', 'i', '3241', '579', 'v', '4807', 'p', 'p', '6313', 'd', '2369', '6713', 'v', '1743', 's', 'q', 'e', 'u', '2019', 's', 'k', 'k', 'n', '8105', '5595']
answer:

b, d, e, i, k, n, p, q, r, s, t, u, v, w, y, z