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: ['a', 'y', '7401', 'e', 'l', '4351', 'p', '5673', 'k', '333', 'o', 'd', 'e', 'j', 'e', '9569', '1795', 'r', 'z', '6059', '4399', '2927', 'n', '9387', '9317', 'b', 'c', 'e']

Answer: a, b, c, d, e, j, k, l, n, o, p, r, y, z


Question: ['p', '9641', '8515', '1207', 'd', 'j', '6617', '5529', 'g', 'a', 'o', 'f', 'y', '4993', '4643', '6087', 'n', '3177', 'y', '9471', '1229', '8211', '7079']

Answer: a, d, f, g, j, n, o, p, y


Question: ['r', '1027', 'h', '4539', 's', 'a', 'i', '5097', '6427', '8701', '9233', 'y', 'k', '4033', 'e', '5873', '8421', 'g', 'e', 'c', '7255', '9439', '2929', 'o', '567', '5587', '2643', 'v', 'i', 'a', 'c', 'u', '1541', '5587', '1773', '9249', '1871', 'h', 'h', '2887', 'd', '9455', 't', '5961']

Answer:
a, c, d, e, g, h, i, k, o, r, s, t, u, v, y