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:
['6209', 'x', 'j', 'w', '7965', '4905', '6297', '4291', '7183', 'a', 'l', '5267', 'r', '5935', 'a', '7865', 'h', 'p', '6117', 'a', 'y', 'y', 't', 'v', '7271', 'e', 'e', 'z', 'i', 'l', '4731', '2059', 'm', '5703', 'k', 'f', '8125', 'e', '7569', 'r', '2287', '593']
answer:
a, e, f, h, i, j, k, l, m, p, r, t, v, w, x, y, z


question:
['m', '8127', '7519', '4543', '2809', '9855', 'n', '6241', 'w', 'w', 'q', 'w', 'p', '8599', '7819', '3817', 'm', 'q']
answer:
m, n, p, q, w


question:
['m', 'h', 'o', '4679', '2939', '5817', '5971', '2059', '3899', '4123', 'v', '4531', 'f', 'e', '825', '7057', 'o', 'r', 'z', 'm', '3295', 'f', '3295', 'u', '5841', 'i', 'b', 'o', '5655']
answer:

b, e, f, h, i, m, o, r, u, v, z