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:
['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:
['9555', '5983', '1853', 'c', 'z', 't', 'p', '9041', 'd', '5919', '1621', '345', 's', '2647', '4261', '8611', 'w', 'x', 'p', '9103', '2599', '5101', '9261', 'k', '7437']
answer:
c, d, k, p, s, t, w, x, z


question:
['9041', 'p', 'a', 'a', 'd', 'z', 's', '2695', '4747', 'w', '1785', '8483', 'k', '1543', '2263', '7651', '1429', 'p', '7243', 'h', 'r']
answer:

a, d, h, k, p, r, s, w, z