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]: ['4041', 'l', 'g', '9571', '9295', '1395', 'l', 'p', 'f', 'w', 'g', '1721', '2421', 'w', 'z', '2235', 'p', '7851']
[EX A]: f, g, l, p, w, z

[EX Q]: ['3473', '4851', '1953', 's', 'k', 'f', 'p', 'm', 'e', 'e', '8097', '4159']
[EX A]:
e, f, k, m, p, s