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:
['4031', 't', 'o', 'c', 'x', '3007', '8329', '6345', '1267', '1017', 'o', 'x', 'l', '4129', 'd', '1987', '487', 'o', 'g', 'j', 'v', 'x', '3983', 'f', 'g', '5759', 'k', 'i', 'o', 'b', 'n', '683', 'j', 'o', 't', '4361', 'u']
answer:
b, c, d, f, g, i, j, k, l, n, o, t, u, v, x


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:
['j', 't', 'k', '8505', '3563', 't', 'j', 'o', 'm', 'd', 'v', 'b', 'u', 'x', 'h', 'd', 'a', '1525', '6401', '7427', '7555', '9977', 'l', 'k', '3497', 'r', 't', '4933', '1263', 'v', '6215', '8789']
answer:

a, b, d, h, j, k, l, m, o, r, t, u, v, x