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.

Input: Consider Input: ['2527', '9123', '8717']

Output: -1


Input: Consider Input: ['333', 'b', '261', 'k', 'p', '7861']

Output: b, k, p


Input: Consider Input: ['2999', 'u', 'q', '8303', 'e', 'c', 'l', 'w', 'k', 'o', 'r', 'c', '4287', '3523', 'u', 'f', 'h', 'z', '8481', '4775', 't', '5437', '3421', '3989', 'n', '4695', '7133', 'g', 'a', '6937', 's', 'c', '4833', '2039', 'q', '2183']


Output: a, c, e, f, g, h, k, l, n, o, q, r, s, t, u, w, z