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.

Example Input: ['2521', '8027', 'm', '193', '615', 'l', '1947', '5949', '6307', 'r', '1015', '743', 'v', '6949', 'b', 'g', '8841', 'c', 'b', '2879']
Example Output: b, c, g, l, m, r, v

Example Input: ['6955', '721', '2763', '8121', '9109', '6341', 'p', 't', 'x', '6963', '1137', 'z', 'u', '1949', '7029', 't', '9539', 'a', 'u', '1873']
Example Output: a, p, t, u, x, z

Example Input: ['n', 't', '4995', '269', 'u', '3281', '7343', 'x', '1965', '1675', '8517', 'h', '617', 'o', '155', 'g', 'v', '7243', 'b', '6615', '9593', 'z', 'g', '2673', '7893', '3199', 'r', 'k', '7425', '8953', '6347', 'q', 'r']
Example Output:
b, g, h, k, n, o, q, r, t, u, v, x, z