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:
['1233', '405', '8901', '7147', '8841', 's', 'v', '3131', 'p', 'd', 'y', '5873', '439']
answer:
d, p, s, v, y


question:
['l', '6819', '1029', '2925', '2361', '5545', '2151', '2681', 'f', 'p', '1263', '2875', 'b', '4665', 'f', 'g', 'p', '4829', '8453', 'z', 'l', '4219', '7517', '25', 'a', '5099', '3693', 'i', '1815', '1541', 'g', '7665']
answer:
a, b, f, g, i, l, p, z


question:
['5487', 'h', '3177', '773', 'f', 'm', '7125', '9543', '4341', 'c', '3593', 'd', '5583', 't', 'a', '533', '3679', 'y', '4001', '5011', 'n', 'a', 'n', '3325', 'q', '3709']
answer:

a, c, d, f, h, m, n, q, t, y