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: ['2697', 's', '8733', 'n', '5871', 'f']

A: f, n, s
****
Q: ['1649', 'l', 'i', '5901', 'o', 'g', '1197', 'a', '9327', '9835', '1095', 'k', '4489', '9149', 'o', '3095', 'z', 'u', 'y', '561', '7419', 't', 'j', '8763', 'v', '339', 'y', 'w', 'v', 'v', '1867', 'd', 'r', 'w', 'h', 'j', '1531', '3841']

A: a, d, g, h, i, j, k, l, o, r, t, u, v, w, y, z
****
Q: ['v', '4803', '2629', '2715', '5779', 'y', 'u', '6481', 'g', 'h', '8029', '127', 'o', 'p', '7347', '9645', 'z', 'a', '3585', 't', '9155', 'o', '5201', 'c', 's', 'j', 'i', 'v', 'm', '3605', '3571', 'a', '2955', 'h', '6295', 'r']

A:
a, c, g, h, i, j, m, o, p, r, s, t, u, v, y, z
****