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: ['6181', 'w', '4663', '5507', 'a', '6607', '869', '2669', 'r', '3629', 'r', 'l', '6599', '8885', 's', '4315', 'z', 'l', 'r', '1225', '8371', '1545', '7169', '1175', 'k', 'p', 'y', '7263', '5537', '8649', '3317', 'q', 'r', 'u', 'd', '4647', 'u', 'y', 'h', '9753', 'q', '725']

Answer: a, d, h, k, l, p, q, r, s, u, w, y, z


Question: ['g', 'p', '2925', 'n', 'o', 'y', '6381', 'l', '4963', 'g', 'm', 'u', 't', '9389', '3787', '7713', '1251', '779', 'i', 'w', '9869', 'y', 'y', '3881', 'k', 't']

Answer: g, i, k, l, m, n, o, p, t, u, w, y


Question: ['b', '9827', '8523', '4851', '4667', '5131', 'a', 'z', '6281', 'h', 'l', '9497', 's', 'w', '3123', '4305', '4061', 'b', 'l', 'f']

Answer:
a, b, f, h, l, s, w, z