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]: ['3395', '7471', 'n', '9537', '1255', '1997', '3085', '4863', '9797', '4275', 'k', 'f', '8973', '3939', 'p', 'q', '4977', '6231', '8745']
[EX A]: f, k, n, p, q

[EX Q]: ['9113', '3625', 'u', '8189', '3649', '259', '5539', '1583', 'g', '4037', 'y', 'v', '8337', 'd', 'q', 'j', 'c', 'h', 'p', '1601', 'z', 'c', 'n', '1767', '1679', '1805', 'm', '4469', '2487', '6015', '973']
[EX A]: c, d, g, h, j, m, n, p, q, u, v, y, z

[EX Q]: ['5431', 'o', 'u', 'l', 'f', 'd', 'r', '1479', '9357', 's', 'v', '6399', 'b', '7937', 't', '8497', 'r', '131', 'h', 'c', 'v', '8879', 'k', 'r', '4687', 'l', '1065', 'r', 'w', 'l', '3305', '461', 'q', 'h', 'b', 'e', 'e', 'w', '5999']
[EX A]:
b, c, d, e, f, h, k, l, o, q, r, s, t, u, v, w