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: ['4925', 'i', 'q', 'k', '7615', 'r', '7217', 'o', '8097', '9151']

A: i, k, o, q, r
****
Q: ['w', '1349', '3393', '7507', '2469', '8531', 'w', '6845', 'k', 'q', '2401', 'f', 'g', 'l', 'n', 'n', 'e', 'q', 'y', 'v', '3077', '4167', 'b', '5517', 'b']

A: b, e, f, g, k, l, n, q, v, w, y
****
Q: ['2255', 'i', 'b', '3863', '3397', '4907', '3979', '3687', '8645', 'm']

A:
b, i, m
****