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:
['565', 'i', '615', '3047', 'm', '195', '7547', '3003', '9213', '9063', 'c', '5099', 'v', '5003', '9053']
answer:
c, i, m, v


question:
['m', 'z', 'd', '4667', 'v', '2881', '887', 's', '9861', 'd', '8821', '125', 't', '4493', '6749', '2983', '309', '6033', 'i', '3421', 'j', '4001']
answer:
d, i, j, m, s, t, v, z


question:
['6649', 'z', 'x', 'o', 'g', '6193', '4445', 'a', 'e', '1605', 'v', '3305', 'p', 'c', '1407', '2075', '8261', '7991', '4745', 'i', 'p', 'j', 'b', 'k', 'j', '5029', '7003', '4677', '5235', 'k', 'r', '3703', '8563', '6581', 's', 'k', 'j']
answer:

a, b, c, e, g, i, j, k, o, p, r, s, v, x, z