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:
['5161', 'v', 'y', '6005', 'y', 'l', '5451', 'z', 'j', 'd', '4597', '9319', '1241', 'g', 'f', 'b', 'g', '683', '763', 'm']
answer:
b, d, f, g, j, l, m, v, y, z


question:
['u', '4021', 'u', 'd', 'j', 'p', 'i', 'z', '3223', 'f', 's', 'l', 'p', 'd', '5031', '1059', '7875', '2097', 'q', 'i', '8813', '2017', 'h', 'l', 'y', '57', '1561', 'f', 'j', 'z', '1901', 'u', 'j', 'x', '6561', '9239', '3333', '8793', '4915', '5821', 'h', 'f', '765', 'x']
answer:
d, f, h, i, j, l, p, q, s, u, x, y, z


question:
['9319', '1089', '4199', '9925', '3041', '5149', '2969', 'k', 'u', 'j', 'd', '9399', '699', '1701', 'c']
answer:

c, d, j, k, u