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:
['9833', '3383', 'h', '3545', '2899', 'y', 'p', 'q', '1901', '3317', '5641', 'v', 'c', 'u', '5521', 'e', '7997', '2439', '5573', '4119', 'k', '8291', '1009', '8253', '405', '233', 'p']
answer:
c, e, h, k, p, q, u, v, y


question:
['3411', 'a', 'v', 'j', '8925', '909', 'h', 'l', 'r', '1371', 'u', '7789', '4813', 'u', 'q', 'i', '8473', 'n', '7191', 'c', '4641', 'e', '5107', 'q', 'z', 't', '105', 'q']
answer:
a, c, e, h, i, j, l, n, q, r, t, u, v, z


question:
['4077', '5601', '2677', '8647', '2609', 'e', 'r', 'p', '4501', '2625', '1185', '6267', 'x', '329', '9001', '9113', '9047', '6771', 'c', '747', 'h', '8343', 's', '3889', 's', '6625', 'l', '5895', 'w', 'x', '2507']
answer:

c, e, h, l, p, r, s, w, x