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:
['u', '1805', 'l', 'l', '5449', 'r', '4471', 'a', 'u', 'c', 'q', '6463', '6717', '7025', '9359', 'q', 'h', '1989', '5497', 'h', 'd', 'c', '135', '5737', '1235', 'v', 'u', 'g', 'p', 't', '9223', '8289', '4489', 'n']
answer:
a, c, d, g, h, l, n, p, q, r, t, u, v


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:
['8995', 'b', 'f', '9971', '9181', 'm', '2009', 'j', 'f', '5807', '6011', '2967', 't', '8397', '2033', 'u', 'q', '6985', '2523', '5611', '5919', 'e', '4149', '5167', 'v', '2895', '8447', 'x', 'm', '4419', 'h', 'q', '9409', '9581', 'l', '3679', '7597']
answer:

b, e, f, h, j, l, m, q, t, u, v, x