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:
['f', '217', '449', 't', 'j', '4097', '5561', '8317', '647', 'u', 'b', '7833', 'r', '9011', 'z', '2753', '2183', 'z', 'o', 'g', '7541', 'b', '8795', '327', 'v', 'e', 't', 'l', '4909', 'k', '7681', 'r']
answer:
b, e, f, g, j, k, l, o, r, t, u, v, z


question:
['8887', '1199', 'r', '7209', 'k', '7567', '7239', 'k', '5123', 'w', '4523', 't', 'd', '5289', '5737', '485', 'w', 't', '7651', 'v', '7213', '7687', 'y', 'w', '7265', 'b', 'b', '3667', 'z', '9935', 'i', 'l', 'u', '6715', 'j', '9815', '8925', '7941', 'w', 'm', '3907', '621', '5523', '5849']
answer:
b, d, i, j, k, l, m, r, t, u, v, w, y, z


question:
['j', 'o', 'y', '5761', '2529', 'v', '8885', 'd', 'f', '9225', 'q', '5803', '3767', 'n', '4493', '9467', '4911', '9903', 'u', 'v', 'm', 'u', '3269', 's', '1481', 'n', 'q', 'v', '5105', '4069', '9125', 'h', 'u', '1903', '9797', '3411']
answer:

d, f, h, j, m, n, o, q, s, u, v, y