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:
['d', '1625']
answer:
d


question:
['c', 'a', 'p', 'p', '4203', '1587', '2953', '9809', '99', '5821', 't', 'i', '4213', '1809', 's', 'l', 'i', 'b', '9233', '3983', '7713', '1807', 'k', 'f', '7825', '5491', 'o', '1347', 'u', 'h', '3967', 'u', 'g', '6775', '1069', '9211', 'i', '3369', 'r']
answer:
a, b, c, f, g, h, i, k, l, o, p, r, s, t, u


question:
['u', '6881', '4647', '3477', 'j', '6103', 'q', 'l', '4699', '3385', '7699', '1659', '2419', '6405', '5527', '9987', '9405', '4385', 'l', 'm', 'f', '1163', 's', 'x', '1683', 'e', 'p', '3619', 'i', '1805', '6543', 'z', '8707', '47', 'd']
answer:

d, e, f, i, j, l, m, p, q, s, u, x, z