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:
['2505', '4199', 'e', '5433', '8795', 'q', 'i', '9357', 'o', '257', '8235', 'b', '1339', 'w', '1463', 'm', '277', '3211', '3863', 'r', 'm', 'i', '5793', '7451', '4787', '4739', 'k', 't', 'o', '7453', '9385', 'v', 'l', 'y', 'f', 'r', 'p', 'w']
answer:
b, e, f, i, k, l, m, o, p, q, r, t, v, w, y


question:
['f', 'w', 'y', 't', '5269', '9989', 'p', 'v', '6609', 'v', 'c', 'q', 'm', '6565', '189', 'm', '3617', 'b', '9147', '665', 'v', '5989', '1511', '3123', '6667', '4661', '185', 'b', '3405', 'b', '6027', 'n', '6973', '505', 'g', '815', '3439', '2069', '291', 'j', 'f', '1121', '8009', 'm', '8353']
answer:
b, c, f, g, j, m, n, p, q, t, v, w, y


question:
['t', '8137', 'y', 'o', 'd', '5495', 't', 'r', 'l', 'm', 'y', 'm', 'z', '3473', '6119', '1377', 'm', 'b', '8417', 'x', '9507', 'j', 'v', 'd']
answer:

b, d, j, l, m, o, r, t, v, x, y, z