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', '9027', 'z', '9601', 'w', '7747', '1135', 'j', '1871', 'd', 'u', 'f', 'd', 'x', 'k', '2009', 't', '4625', 'm', '1619', 'm', 'm', '3107', 'x', '3957', '2495', 'j', '201', 'a', '4635', 'r', '7407', 'b', 'r', 'z']
answer:
a, b, d, f, j, k, m, r, t, u, w, x, z


question:
['9555', '5983', '1853', 'c', 'z', 't', 'p', '9041', 'd', '5919', '1621', '345', 's', '2647', '4261', '8611', 'w', 'x', 'p', '9103', '2599', '5101', '9261', 'k', '7437']
answer:
c, d, k, p, s, t, w, x, z


question:
['t', 'k', '5697', '5773', 's', '9413', 'u', 'd', 'h', '2827', 'n', 'k', '577', 'y', '3249', '4035', 'v', '2335', 'v', 'x', '3355', '8641', 'a', '4947', '617', '9245', 'o', '6357', 'c', 'x', 's', '889']
answer:

a, c, d, h, k, n, o, s, t, u, v, x, y