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: ['9555', '5983', '1853', 'c', 'z', 't', 'p', '9041', 'd', '5919', '1621', '345', 's', '2647', '4261', '8611', 'w', 'x', 'p', '9103', '2599', '5101', '9261', 'k', '7437']

A: c, d, k, p, s, t, w, x, z
****
Q: ['2293', 'p', '9787', '7241', '8689', 'u', '3141', 'h', 'c', 'b', 'f', 's', '319', 'c', 'p', '6909', 'p', 'f', '1717', 'd', '2285', 's']

A: b, c, d, f, h, p, s, u
****
Q: ['9029', '3299', '7265', 'l', 'a', '5013', 'u', '273', '2717', 'c', 'w', '6881', 's', 'y', '7771', '1677', '5993', 'r', '6307', '5195', 'j', '6019', '9487', '2643', 'c', 'v', 'f', '4881', '6225', '9375', '6109', '1575', '4071', 'o', 'e', '4227', 'y', 's']

A:
a, c, e, f, j, l, o, r, s, u, v, w, y
****