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: ['7367', '9757', '9431', 'h', 'a', 'k', '5833', '6237', 'g', '3585', '8665', 'g', '7517', '1561', 'p', 'p', '1307', '3325', 'q']

A: a, g, h, k, p, q
****
Q: ['4787', 'c', '1727', '9863', '8147', '3931', 'b', '1133', '3023', '7427', '7837', 'n', '7921', 'o', 'c', '3973', '1949', 'x', 'g', 'b', 'd', '8559', '8661', '4465', 'z', '369', 'q', 'e', 'y', '8629', '7665', 'i', 'r', 'n', 'z', '9115', '1393', '4899']

A: b, c, d, e, g, i, n, o, q, r, x, y, z
****
Q: ['q', '9033', 'p', 'z', '1743', '247', '967', '445', '9849', 'f', '9113', 'b', 'g', '6041', 'j', '927', 'i', 'p', '6821', 'q', '6701', 'f', 'j', 'o', 'y', 'c', '7981', 'b']

A:
b, c, f, g, i, j, o, p, q, y, z
****