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: ['p', '9641', '8515', '1207', 'd', 'j', '6617', '5529', 'g', 'a', 'o', 'f', 'y', '4993', '4643', '6087', 'n', '3177', 'y', '9471', '1229', '8211', '7079']

A: a, d, f, g, j, n, o, p, y
****
Q: ['s', 'c', 'e', '2457', '9413', 'r', '9949', 's', 'z', 'e', 'a', 'o', '7207']

A: a, c, e, o, r, s, z
****
Q: ['a', 's', '4289', 'q', '2557', 'v', '6035', '3373', 'y', 'v', '3613', '5917', 'q', 'b', '3487', '4313', '6547', '8103', 'a', 'a', 'm', 'j', 't', '4105', '7369', '3427', '9927', 'g', '9607', 'r', 't', '4531', '1781', '481', 'p', 'b', 'w', 'b', 'g', 'y']

A:
a, b, g, j, m, p, q, r, s, t, v, w, y
****