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:
['d', 'a', '6931', 'c', 'u', 'z', '9713', 'v', 'm', 'e', 'k', 'o', '9705', 'a', '5373', 'c', '2983', '8097', 'h', '3039', 'g', 'f', 'n', 'v', '853', '8227', '7573', 'j', 'h', 'k', 'o', 'k', '8897', 'd', 'g', 'd', 'd', '4039']
answer:
a, c, d, e, f, g, h, j, k, m, n, o, u, v, z


question:
['1801', 'q', '5101', '8863', '2309', 'p', '8789', '9529', '6135', '5523', 'f', '8889', '7639', 'k', '263', '5751', '5529', 'g', '1451', '4143', 'e', '6987']
answer:
e, f, g, k, p, q


question:
['s', '7587', 'c', 'y', 'j', 'm', 'b', '1119', 'y', 'm', '5121', '3373', '9917', 'u', '2811', '9097', 'f', '2023', '5545', 'q', 'j', '9375', '6229', 'd', '7595', '5753', '4009', 'w', 'e', '4123']
answer:

b, c, d, e, f, j, m, q, s, u, w, y