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:
['7367', '9757', '9431', 'h', 'a', 'k', '5833', '6237', 'g', '3585', '8665', 'g', '7517', '1561', 'p', 'p', '1307', '3325', 'q']
answer:
a, g, h, k, p, q


question:
['e', '2239', 'l', '8309', 'i', '2613', 'i', '611', '6481', 'j', 'v', '1867', '415', '269', '8053', '3369', 'q', 't', '2303', '7729', '1059', '6135', '3299', 'd', '6855', '207', '6227', '7859']
answer:
d, e, i, j, l, q, t, v


question:
['3773', 'r', '399', '3115', 'q', 'i', 'd', '2763', 'j', 'g', 'y', 'x', 'h', 'l', 'w', 'h', 'k', 'j', 'd', 'g', '2707', 'm', 'c', '5955', '2449', 'h', '5899', '2409', 'g', 'j', 'n', '6591', 'd', '4239', '1005']
answer:

c, d, g, h, i, j, k, l, m, n, q, r, w, x, y