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]: ['s', 'u']
[EX A]: s, u

[EX Q]: ['9555', '5983', '1853', 'c', 'z', 't', 'p', '9041', 'd', '5919', '1621', '345', 's', '2647', '4261', '8611', 'w', 'x', 'p', '9103', '2599', '5101', '9261', 'k', '7437']
[EX A]: c, d, k, p, s, t, w, x, z

[EX Q]: ['339', '2019', '3401', '2987', 'd', '3177', '8761', 'g', '6069', 'u', 'l', 'h', '1749', '5861']
[EX A]:
d, g, h, l, u