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:
['4417', 'x', '4641', '885', '8485', 'd', '7057', '8519', 'm', 'i', 'l', '4627', '3069', 'v', '5011', 'u', '6673', 'h', '4541', 'j', '2337', '8175', '4797', 'f', '9109', 'q', 'q']
answer:
d, f, h, i, j, l, m, q, u, v, x


question:
['1121', 'j', '1433', 'g', 'l', '1479', '1699', 'j', 'a', '8507', 'd', 'a', '5229', 'k', 'x', '4549', 'e', 'p', '1367', 'u', 'd', '785', '215', 'e', 'f', 'a', '101', '7575', '7965', 'p', 'i', '5637', '1005', 'i', 'y', '181', 'r']
answer:
a, d, e, f, g, i, j, k, l, p, r, u, x, y


question:
['5391', '1589', 'g', 's', '8319', '6367', 't', 'm', '6459', '7761', '1819', 'm', 'b', '3523', '731', '8717']
answer:

b, g, m, s, t