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:
['o', '4167', 'b', '1651', '8327', '9219', 'o', 'v', '5841', '6057', 'i', 'q', 'o', 'r', 'a', '7069', 'y', 'h', 'd', '3775', 'j', 't', '3663', '55', '7117', 'e', 'u', 'm', '931', '5777', '8773', '4891']
answer:
a, b, d, e, h, i, j, m, o, q, r, t, u, v, y


question:
['a', '533', '67', 'z', 'z', '9283', 'o', 'a', '7045', '1521', 'm', 'h', 'q', '4173', '7497', '319', '5721', '6097', 'i', '9829', '1801', '7347', 'r', 'z', '239', '4279', 'e', 'k', 'r', 'v', '6653', '599', '8597', 'd', 'r']
answer:
a, d, e, h, i, k, m, o, q, r, v, z


question:
['a', 'h', '2877', 'u', '6063', 'r', 'f', '6623', '5957', '731', 'i', 's', 's', '2111', '5767', 'm', '3795', 'm', '4953', 'r', 'o']
answer:

a, f, h, i, m, o, r, s, u


