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: ['8815', 'w', '8629', 'y', '3891']

A: w, y
****
Q: ['u', 'w', '401', 't', 'g', 'h', 'g', '8073', '9597', '1347', '7835', '5007', '977', 'p', '7679', 'b', '4883', '4931', '999', 'r', '1181', 'x', '2063', 'l', 'w', 'i', 'l', 'x', 'i', '9057', '5007', 'w', '743', '1635', 'y', 'f', '9227', 'z', '5227', 'd', '7129', 'k', '7657']

A: b, d, f, g, h, i, k, l, p, r, t, u, w, x, y, z
****
Q: ['x', 'q', '4695', '1179', 'm', '4409', 'x', 'k', '5319', 'l', 'n', 'p']

A:
k, l, m, n, p, q, x
****