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:
['m', '3809', 'l', 'k', '1929', '7963', 'n', 'u', '2125', 'g', 'o', '8325', 'o', 'h', 'y', '3025', 'e', 'e', 'c', 'x', '8445', '4979', 'z', 'f', '4201', '4765', 'g']
answer:
c, e, f, g, h, k, l, m, n, o, u, x, y, z


question:
['2313', '2073', 'd', 'e', 'o', '793', '4999', 'f', 'c', '4473', '4519', 'u', 'n', 'k', '69', '475', 'a', 'j', 'q', 'x', '5869', '9523', 'z', 'v', '9265', '5989', 'p', 'm', 'g', 'y', 'b']
answer:
a, b, c, d, e, f, g, j, k, m, n, o, p, q, u, v, x, y, z


question:
['1495', 'b', 'j', 'd', 'u', 'e', '9253', 'b', '1931', '571', '5715', '6213', 'g', 'd', '6295', 'h', '3125', '9101', '3793', '6303', '8747', '9119', 'v', 'i', '7277', 'j', 'e', 'f', 'c', '3769', 't', '2023', 'p', '7143', 'x', 'f']
answer:

b, c, d, e, f, g, h, i, j, p, t, u, v, x