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]: ['j', '917', 'w', 't', '8873', '1431', '8059', '7041']
[EX A]: j, t, w

[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]: ['9681', 'm', '2391', 'o', '3263', 'c', 'o', 'r', '8523', 'z', 'i', '8745', 'e', '7353', 'w', 'm', '8857', 'q', 'x', '1121', '2421', '5261', '5057', 'g', 'c', 'j', '1691', 'm', '2589', '6493', 'l', 'q', 'y', '9259', 'd', 'v', 'z', '4253', 'o', '4537', 'y', 'd', '5181', 'f', 'b']
[EX A]:
b, c, d, e, f, g, i, j, l, m, o, q, r, v, w, x, y, z