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:
['4653', 'e', 'c', 'j', '6739', '3963', 'q', '4649', 'v', 's', 'j', '9757', '8075', '6253', '4365', 's', '9101', 'd', '6989', 't', '5687', '7389', '139', '4029', '5073', 'q', 'e', '2455', '1075', 'j', '1329', 'l', '4689', 't', 'z', '4179', 's', 'l', 'w', 'n', '6569', '8907', 'v', '605', 'y']
answer:
c, d, e, j, l, n, q, s, t, v, w, y, z


question:
['7441', '7967', '2011', '1383', 'i', '3623', 'b', 'y', 'e', '1593', 'r', 'a', 'd', 'b', '6159', '3931', '989', '435', 'o', 'y', 'j', 'w', '7669', 'y', '5781', 'u', '531', '7467', '3971', '8139', 'w', 'a', '5113', '9461', '8377', '7431', '6975', '6055', '7307', 'v']
answer:
a, b, d, e, i, j, o, r, u, v, w, y


question:
['a', '3925', 'r', '8331', 'i', 't', 'q', 'i', 's', '9693', 'h', 'd', '6007', '6731', 'w', 'p', 'm', 'p', '3721', '4157', 'b', '8779', 'h', '711', 'u', '7795', '277', 'p', 'a', 'l']
answer:

a, b, d, h, i, l, m, p, q, r, s, t, u, w