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:
['k', '6595', '1595', 'v', 'h', 'b', '8815', '6681', 'j', '7581', 'p', '9095', '5453', 'r', 'y', '7755', 'x', '1853', 'k', 'q', 'u', 'j', 'q', '9651', 'o']
answer:
b, h, j, k, o, p, q, r, u, v, x, y


question:
['1931', 'c', 's', '8767', 'z', '8977', '9249', '365', 'p', '7187', 'p', '961', 'k', 'k', '423', '5999', '4697', '6251', '6441', '1821', 's', 's', 'f', '5365', 'z', '5113', 'y', 'k', 'i', '5627', 'u', 'w', '4103', '8035', '7105', 'o', 'n', 's', 'y']
answer:
c, f, i, k, n, o, p, s, u, w, y, z


question:
['4135', 'm', 'i', 'c', '8931', 'n', 'd', 'h', 's', 'w', '4045', '7219', 'g', '4409', 'h', '5487', '5989', '9551', '3635', '2755', '9751', 'd', '2379', 'r', 'p', '4483', 'g', 'b', 'h', '717', '3293', 'w', 'j', '7383', '1141', '4659', '3479', '5287', '9935', '677']
answer:

b, c, d, g, h, i, j, m, n, p, r, s, w