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: ['w', 'g', '1649', 'a', '2115', '6763', 'r', 't', 'l', 's', 'y', '5659', 'a', 'b']

Answer: a, b, g, l, r, s, t, w, y


Question: ['7595', '5303', '3985', 'n', 'w', 's', 'r', 'f', '8237', 'q', 'y', 'f', '3121', '2463', '4597', 'q', '6801', 'f', 'i', '8563', '3267', 'k', '6157', 'f']

Answer: f, i, k, n, q, r, s, w, y


Question: ['1555', 'i', 'f', '4901', 'z', 'z', '9581', '8941', '815', 'h', '6777', 't', 'g', 'g', '2841', '9881', '3163']

Answer:
f, g, h, i, t, z