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.

Q: ['l', 'u', '3901', '341', '5801']

A: l, u
****
Q: ['7071', 'h', '837', 'z', 'c', '2217', 'c', '6341', '6607', 'g', '3569', 'a', 'h', 't', 'b', 'f', 'g', 'f', 'l', 'b', 'x', 'o', 'r', '8949', '8071', '1507', 'v']

A: a, b, c, f, g, h, l, o, r, t, v, x, z
****
Q: ['795', 'o', '4861', 'r', 's', 'n', 'w', 'd', 'o']

A:
d, n, o, r, s, w
****