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: ['333', 'b', '261', 'k', 'p', '7861']

Answer: b, k, p


Question: ['w', 'i', '4383', '7667', '9617', 'y', 'a', '8051', 'w', '4857', 'y', '3953', 'u', 'o', 'y', 'i', '9201', 'g', '1807', '5367', 'g', '5263', '3995', '6665', '3113', '9433', '6315', 'm', '845', 'x', 'c', 'v', 'h', '1491', 'g', '3519', 'x', 'b', '7695']

Answer: a, b, c, g, h, i, m, o, u, v, w, x, y


Question: ['l', 'z', 'u', '9557', '4991', '9675', 'd', '8229', '469', '2229']

Answer:
d, l, u, z