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: ['o', '1099', 'r', '8995', 'o', '2909']

A: o, r
****
Q: ['9923', 'x', '1901', 'v', '1459', '7503', '3829', '4929', 'k', 'c', '3329', '8793', 'n', 'a', '7249', 'b', 'l', 'l', 'm', 'p', 'b', 'a']

A: a, b, c, k, l, m, n, p, v, x
****
Q: ['d', 's', '3571', 'l', 'y', '9845', '9429', 'h', '8769', 'd', '893', 'h', '3395']

A:
d, h, l, s, y
****