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]: ['l', '6819', '1029', '2925', '2361', '5545', '2151', '2681', 'f', 'p', '1263', '2875', 'b', '4665', 'f', 'g', 'p', '4829', '8453', 'z', 'l', '4219', '7517', '25', 'a', '5099', '3693', 'i', '1815', '1541', 'g', '7665']
[EX A]: a, b, f, g, i, l, p, z

[EX Q]: ['n', '9571', '2983', '7597', 'v', 'y', '1993', '1403', '8309', '7043', 'c', '7329', 'p', '4479', 'p']
[EX A]: c, n, p, v, y

[EX Q]: ['t', 's', '1515', '223', '4353', '1077', '3155', 'x', 'u']
[EX A]:
s, t, u, x