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: ['i', 's']

A: i, s
****
Q: ['o', 'c', '6469', 'x', '8815', '4441', '6193', 'u', 'm', 'a', '9879', 'p', '8335', 'c', 'z']

A: a, c, m, o, p, u, x, z
****
Q: ['933', '6563', '4595', 'i', 'o', '2517', 'j', '5097', '6971', '7995', 'o', '6911', '7671', '7033', 'k', '5699', '5649', 'n', 't', 'n', 'q', '937', '3441', '7749', '855', '397', 'd', 'w', 'z', '581']

A:
d, i, j, k, n, o, q, t, w, z
****