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: ['p', '2923', 'e', 'k', '5433', '605', '5079', 'k', 'p', 'x', '4845', '4099', '6795']

Output: e, k, p, x


Input: Consider Input: ['y', 'g', '107', '4899', '6357', '9777', 'k', '1865', '7029', 'q', 'x', '7051', 's', '6125', '4285', '2731', 'z', 'a', '737', '6137']

Output: a, g, k, q, s, x, y, z


Input: Consider Input: ['7275', '8031', 'o', 'o', '2471', '7523', '5183', '931', 'r', 'v', '8259', 'm', '7807', 'h', '7005', '8033', '9811', 'e', '5859', 'o', '3461', 'b', 'b', '4449', 'b', '2637', 'r', '7787', 'u', 'b', '3311']


Output: b, e, h, m, o, r, u, v