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.
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Question: ['d', 'p', 'k', '9679', 'x', 'j', '7481', '1815', 't', 'w', '6513', 'j', '5079', '5219', 'p', '9545', 'a', '1931', '9973', '8125', '5169', '2791', 't', 'd', '2057', 'e', 'x', 'y', '7409', 'u']

Answer: a, d, e, j, k, p, t, u, w, x, y


Question: ['i', 'h', '8299', 'e', 'c', '5543', '5241', 'f', '3985', 'f', 'z', '1245', 'e', 't', 'g', '5199', '9217', 'q', 'j', 'p', '767', 'z', '1803', 'k', '7303', '3187', '2507', '6471', '3337', '6037', '9291', 'a', 'l']

Answer: a, c, e, f, g, h, i, j, k, l, p, q, t, z


Question: ['r', 'l', 'i', '8513', '9041', 'c', '4245', '3141', '5271', '8387', '687', 'b', 'v', 'z', '5199', '6119', 'p', '9017', '217', 'e', 'd', '6653', '3957', 'o', 'p', '4505', '3625', '3301', '3273', 'd', 'g', 'l', 'd', '5017', 'r', '8453', '6601', 'e', '5887']

Answer:
b, c, d, e, g, i, l, o, p, r, v, z