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:
['d', '4377', '9271', '8053', '9519']
answer:
d


question:
['3035', 'f', 'k', 'e', '3023', 'p', '9667', '5277', '4757', '8433', 'g', '1399', '7721', 'n', 'p', '7469', '7581', '5679', 'g', 'q']
answer:
e, f, g, k, n, p, q


question:
['1851', 'h', '1659', '8007', 'j', 'q', 'v', 'u', 'e', '9975', '9673', '9559', '3897', '6343', '9685', '5349', 'g', '3281', '9705', 'b', 'n', 'l', '1543', '3595', 'i', '9693', '505', 'e', 'm', '8049', 'b', 's', '8749']
answer:

b, e, g, h, i, j, l, m, n, q, s, u, v