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]: ['2521', '8027', 'm', '193', '615', 'l', '1947', '5949', '6307', 'r', '1015', '743', 'v', '6949', 'b', 'g', '8841', 'c', 'b', '2879']
[EX A]: b, c, g, l, m, r, v

[EX Q]: ['815', '6967', '6553', 'r', 'y', '3641', 'q', 'b', '6131', '4289', 'w', '6093', '6055', 'i', 'b', 'y', '5107', 'v', 'g', '9709', 'x', 'i']
[EX A]: b, g, i, q, r, v, w, x, y

[EX Q]: ['l', 'f', 'n', 'a', '979', '1237', '5497', 'y', '6725', 'w', '4273', 'q', 's', 'v', 'j', 'v', '3719', 'f', 'v', 'r', '9599', 'y', '3295', 'l', 'g', 'h', 'g', 'o', '9061', 'e', 'e', 't', 'y', 'e', 'f', 't', 'k', '2961', 'c', 'v']
[EX A]:
a, c, e, f, g, h, j, k, l, n, o, q, r, s, t, v, w, y