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', '917', 'w', 't', '8873', '1431', '8059', '7041']
answer:
j, t, w


question:
['o', '5503', '5837', '4539', '7631', 'm', '2641', 'p', '7901', '8117', 'z', '3373', '3215', 'v', 'a', '5949', 'w', '9049', 'd', 'a', 'l', 'v', 'l', 'n', 'w', 'r', 'j', '9031', '9609', '4209', 'c', '7453', '5855', '2883', '5941', 't', '4283', 'x', 'x', 'n', 'c']
answer:
a, c, d, j, l, m, n, o, p, r, t, v, w, x, z


question:
['n', '7115', 'd', '7875', 'u', '9313', '699', 'i', '4991', 'x', 'i', '7089', '4617', '689', 't', '4845', '7327', 'k', '5727', '4175', 'q', '4093', 'e', 'a', '7465', 'o', '335', '9485', 'p', 'c', 'g', '7343', '5485', '409', '161']
answer:

a, c, d, e, g, i, k, n, o, p, q, t, u, x


