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]: ['2293', 'p', '9787', '7241', '8689', 'u', '3141', 'h', 'c', 'b', 'f', 's', '319', 'c', 'p', '6909', 'p', 'f', '1717', 'd', '2285', 's']
[A]: b, c, d, f, h, p, s, u


[Q]: ['a', 'p', 'y', 'l', 'l']
[A]: a, l, p, y


[Q]: ['5095', '1947', 'v', 'k', '5771', '4359', 'm', 'o', '6219', 'b', 'o', 'z', '1315', '7789', '5553', '8467', '8929', '1767']
[A]:
b, k, m, o, v, z