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.
--------
Question: ['p', 'p', '7899', 'u', '971', '7289', 't', '5217', 'k', 'z', 'y', 'y', '6905', '9499', '4085', 'x', '955', 'v', 'j', '9049', '7927', '1757', '193', '2181']

Answer: j, k, p, t, u, v, x, y, z


Question: ['2995', '8179', '8131', '5655', 'j', 'q', 'l', '3193', '1823', 'y', 'n', '7645', 's', '5665', 'r']

Answer: j, l, n, q, r, s, y


Question: ['d', 'x', 'p', 'y', '5221', '3467', '81', 'c', '8687', '5515', '207', 'y', 'l', '9813', '5065', 'n', 'u', 'g', '5527', '8923', 'h', 'j', 'p', '3135', '3379', '5079', 'k', '8693', '6851', '1565', '9081', 'a', 'k', '7943', 'g', 'q', '8491', '6953', 'z', 'm']

Answer:
a, c, d, g, h, j, k, l, m, n, p, q, u, x, y, z