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:
['e', '1251', 'y', '6689', '6389', 'h', 't', '503', '5093', 'e', '923', '7051', 'm', 'u', '4501', '3289', '6887', '8341', 'o', '3671', 'n', 'w', '7749', 's', 'j', 'o', '8429', 'q', 'v', 'p', 'd', 'g', 'i', 'f']
answer:
d, e, f, g, h, i, j, m, n, o, p, q, s, t, u, v, w, y


question:
['5463', '5683', 'w', '4071', '3997', 'i', '9677', 'q', 'l', 'v', 'w', '5325', '197', 'g', 'g', '3227', '3477']
answer:
g, i, l, q, v, w


question:
['6331', '3875', 'l', '9815', 'm', '1979', 'l', 'z', '4591', 'm', 'p', 'k', '1987', '23', 'a', 'i', '3445', 'p', '9641', 'y', '6033', '9919', 'u', 'i', '9677', '3539', '7367', '1135', '8263', '4205', 'n', 'i', '5149', 'e']
answer:

a, e, i, k, l, m, n, p, u, y, z