Given the task definition and input, reply with output. 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.

['4505', 'g', 'b', 'l', 'l', '9997', 'g', 'u', '9663', 'z', 'h', '4991', '8483', 'e', '8411', '197', 'k', '133', '9737', 's', '2725', 'o', 'a', '9839', '2597', '6147', '9209']

a, b, e, g, h, k, l, o, s, u, z