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: ['d', 'i', 't', '719', '5815', 'g', 'd', '67', '6931', '7981', '2151', '2767', '6403', '2121', '117', '5049', '4191', '9357', '1899', '5107', 'z', 'g', '2579', 't', 'q', '5923', 'x', '2927', 'y', 'k', 'a']

A:
a, d, g, i, k, q, t, x, y, z
****