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:
['j', 'r', 'z', 'f', '1485', '2419', 't', 'd', '6023']
answer:
d, f, j, r, t, z


question:
['m', '7807', 'n', 'w', '5097', '1023', '2723', 'u', '3055', '7285', 'f', 'm', 'w', '5197', '9743', '7519', '4451', 'c', 't', '1939', '5847']
answer:
c, f, m, n, t, u, w


question:
['533', '5075', '6107', '2835', '453', '4103', '2083', 'g', '9853', '8219', '5551', 'e', '9817', '2795', '4933', '773', 's', '9173', 'd', '2195', '2303', 'z', '1387', 'b', 'b', '4781', '8877']
answer:

b, d, e, g, s, z