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:
['1799', '6409', '9257', '5923', 'm', 'j', '2565', '715']
answer:
j, m


question:
['6585', 'i', 'p', '5623', '3557', '8011', 'c', '6389', 'h', 'h', 'd', '1823', '5567', 'v', 'p', 'x', 'c', '2161', '3649', 'o', '6227', 'f', '9975', 'd', 'm', '2587', 'o', 't', 'k', '7637', 'm', 'l']
answer:
c, d, f, h, i, k, l, m, o, p, t, v, x


question:
['9197', 'v', '3183', 'r', 'w', 'k', 'j', 'j', 'f', 'n', 'd', '6389', '6189', 'w', '2443', '5989', '6585', '9819', '5433', 'x', '9071', 'z', 'q', '889', '1091', 'q', '5529', '9239', '7393', '7155', '2933', '4961', 'e', '3805', '4017', '5721', '8383', '2117', '5083', 'i', '2057']
answer:

d, e, f, i, j, k, n, q, r, v, w, x, z