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', 'i']

A: i, l
****
Q: ['7917', '2295', 'q', 'v', '9373', 'w', 'n', 'q', '5803', 'g', 'k', 'm', '2167', 'k', '6425', 'x', 'g', '341', 't', 'u', '8829', 'h', '4333']

A: g, h, k, m, n, q, t, u, v, w, x
****
Q: ['x', 'v', '1101', '139', '3613', 'k', 's', 'g', '349', 'w', '7423', '6987', 'z', '2275', 'x', 'a', '2335', 'o', '5115', 'd', '1893', 's', '9961', 'f', 'i']

A:
a, d, f, g, i, k, o, s, v, w, x, z
****