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.

[EX Q]: ['r', 's', '2471', 'n', '635', 'k', '3551', '7041', '8765', '1221', '8439', '7773', '6471', 'u', 'p', '2093', '6479', '1435', '6881', 'a', 'y', 'm', 'r', '1627', 'w', 'k', 'b', '3095', '9059', '285', 'y', 'a', 'm', 'x', '637', 'i', '3407', 'e', 'e']
[EX A]: a, b, e, i, k, m, n, p, r, s, u, w, x, y

[EX Q]: ['3947', '4809', 'b', 'a', '4769', '4179', '535', '5965', 'f', 'j', '2265', 'w', '3103', 'u']
[EX A]: a, b, f, j, u, w

[EX Q]: ['s', 'i', 'u', 'a', 'u', '1027', '1697', 'z', 'n', '5859', 'u', 'g', 'h', '5467', '8079', 'd', '3371', 'b', 'n', 'm', '5787', 'j', '1601', '679', '4505', '4659', '1941', '9911', '7519', 'w', 'r', 'u', 'j', 'a']
[EX A]:
a, b, d, g, h, i, j, m, n, r, s, u, w, z