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.

[Q]: ['c', '7039', 'g', '1899', 'r', '507', 'c', '2587', '3865', '1729', '3927', 'r', '3535', '2791', 'm', 'l', 'r']
[A]: c, g, l, m, r


[Q]: ['2349', 'p', 'a', '435', 'y', 'h', '3249', 'o']
[A]: a, h, o, p, y


[Q]: ['m', 'c', 'c', '4987', '2077', '6919', '9783', 'v', '6115', 'y', '1077', '5591', '847', '1303', 'e', '3605', 'x']
[A]:
c, e, m, v, x, y