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:
['9223', 'w', '8631', '4453', '9975', 'y', '9747', 'g', '7077', '2593', '6015', 'n', '7345', 'i', '7807', '299', 'q', '3629', '2545', 'k', 'm', 'q', '5155', '5633', 'x', 'q', 'i', '27', 'f', '7919', 'p', '4835']
answer:
f, g, i, k, m, n, p, q, w, 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:
['2631', 't', '3171', '4527', 'a', '4435', 'w', '5813', 'h', 'o', '1415', '6035', 'w', 'b', 'n', '7575', 'i', '4247', '3511', 'n', '5315', 'w', '4867', 'e', '6677', 'd', 't', 'g', 'h', '831', '6815', '6559', '9703', '3449', 'l', '2373', 'w', '6965', '5021', '5851', '5145', '2987', '2597']
answer:

a, b, d, e, g, h, i, l, n, o, t, w