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]: ['x', 'b', '1467', 'y', '2101', 'y', 'm', '2745', 'z', '429', '7523', 'e', 'f']
[A]: b, e, f, m, x, y, z


[Q]: ['l', 'i']
[A]: i, l


[Q]: ['t', 'd', 'e', 'k', 'f', 'm', '4623', '6555', 'z', '9499', '3307', '1399', '339', '291', '8477', '8635', 'u', '4295', 'a', 'p', 'p', '8357', 'm', '2709', 'r', 'n', '8281', 'j', '5183', 'c', '6281', 'a', 's', '531', '9059', '2357', '8179']
[A]:
a, c, d, e, f, j, k, m, n, p, r, s, t, u, z