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: ['q', 'g', 's', 'g', 'z', '987', '777']

A: g, q, s, z
****
Q: ['i', 'x', 'n', 'w', '8915', 'd', 'd', 'd', '6025', '7861']

A: d, i, n, w, x
****
Q: ['e', '6135', 'c', '9073', 'o', '7065', 'k', '2831', 'k', 'j', '8955', '8655', 'h', 'r', 'q', '6397', 'h', '2499', '6047', 'x']

A:
c, e, h, j, k, o, q, r, x
****