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: ['7653', 'n', '697', '4565', 't', '7275', '2429', '1365', '7059', 'o', '8053', 'j', '2837', '957', '851', 'z', 'd', 'd', 'y', 'c', '7467', 'o', 'i', '9519', 'q', 'g', '7911', 't', 'g', '3439', '5821', '8433', 'k', 'z', 's', 'g', '685', 'i', 't', 'r', '6881']

Answer: c, d, g, i, j, k, n, o, q, r, s, t, y, z


Question: ['4213', '3595', '7937', 'y', '5723', 'v', 'b', '7007']

Answer: b, v, y


Question: ['8361', '9155', 'g', '5227', '7837', '1407', 'c', 'q', '4479', 'a', 'u', 'o', '5563', '4589', 'z', '4113', '5685', 'w', '171', 'i', 'u', 'l', '1169', '9285', '3865', 's', 't', 'z', 'i', 'a', 'i', 'k', 'e', 'n', '943']

Answer:
a, c, e, g, i, k, l, n, o, q, s, t, u, w, z