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: ['r', '4655', 'm', 'l', '4371', 'o', '5331', '5469', 'j', 'u', '4915', 'v', 'i', 'f', 'j', '6139', 'y', '2423', '1271', '2289', '5565', '7561', '9697', 'e', 's', 'u', '9581', 'y', '6095', '5047', '625', '9047', 'd', 's', '8307', '3615', '8145']

Answer: d, e, f, i, j, l, m, o, r, s, u, v, y


Question: ['3147', '9807', '5313', '6311', '737', '1555', '5803', '3437', '5665', '3973', 'o', 'f', '7871', '1721', '7833', '2933', 'b', 'b', 'n', 'm', 'k']

Answer: b, f, k, m, n, o


Question: ['b', '4603', 'm', '6447', 'q', '1277', 'q', '2933', 'i', 'z', '6211', 'k', 'c', 'h', 'e', '9849', '1369', '9957', '5029', '9729', '6477', 'w', 'd', '3303', 'n', 'v', 'b', '4595', 'v']

Answer:
b, c, d, e, h, i, k, m, n, q, v, w, z