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:
['4031', 't', 'o', 'c', 'x', '3007', '8329', '6345', '1267', '1017', 'o', 'x', 'l', '4129', 'd', '1987', '487', 'o', 'g', 'j', 'v', 'x', '3983', 'f', 'g', '5759', 'k', 'i', 'o', 'b', 'n', '683', 'j', 'o', 't', '4361', 'u']
answer:
b, c, d, f, g, i, j, k, l, n, o, t, u, v, x


question:
['i', 'h', '8299', 'e', 'c', '5543', '5241', 'f', '3985', 'f', 'z', '1245', 'e', 't', 'g', '5199', '9217', 'q', 'j', 'p', '767', 'z', '1803', 'k', '7303', '3187', '2507', '6471', '3337', '6037', '9291', 'a', 'l']
answer:
a, c, e, f, g, h, i, j, k, l, p, q, t, z


question:
['9197', '7595', '2973', 'c', 'i', '1429', '6283', '5951', 'm', '577', 'c', '7091', 's', 'r', 'd', '8773', '9739', '8381', '2125', '793', 'j', '1565', 'f', 'y']
answer:

c, d, f, i, j, m, r, s, y