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:
['a', 'p', 'y', 'l', 'l']
answer:
a, l, p, y


question:
['z', 'l', '1759', 'k', '8197', 'v', '931', '2587', '7219', '3455', 'e', '8135', 'm', 'n', 'm']
answer:
e, k, l, m, n, v, z


question:
['e', '4661', 'u', 'e', '5701', 'y', 'n', 'f', 'r', '7213', '9405', '2321', 'k', '5537', 'y', 'f']
answer:

e, f, k, n, r, u, y