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: ['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: ['a', 'w', 'm', 'g', 'c', '5475', '7391', 't', '1049', 'p', 'd', '1397', 'k', 'x', 'j', '2525', 'f', '741']

A: a, c, d, f, g, j, k, m, p, t, w, x
****
Q: ['2961', 'a', 'k', '8447', '3629', '6307', 'k', '3267', 'm', 'o', '2475', 'k', '6677', 'd', '4049']

A:
a, d, k, m, o
****