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.

['9947', '3353', '8643', '4621', '4857', 'y', '7075', 'c', '8911']
c, y

['x', 'i', 'k', 'c', 'f', '3057', '481', '5887', '847', 'c', 'x', 't', 'g', '5805', 'a', 'i', '2885', '403', 'x', 'c', '4815', '2765', 'c', '5181', 'l', 'e', '3843', '1171', 'u', '7867', 'z', 'e', '9349', '5011', 'h', 'x', '3193', 'i', '4595', '8621', '6007', '1879']
a, c, e, f, g, h, i, k, l, t, u, x, z

['o', '9637', '8133', '9665', 'f', 'e', 's', 'o', '5547', 'b', 'j', 'u', 'w', '4105', 's', 'y', 'i', '9989']

b, e, f, i, j, o, s, u, w, y