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: ['o', '1099', 'r', '8995', 'o', '2909']

Answer: o, r


Question: ['z', '5601', '5675', 'w', 's', 'z', '9213', '9563', '1699', 'p', 'g', 'm', 'c', '9279', '4481', 'p', 'n', '2389', 'c', '503', '1901', '8827', '1701', '1607', '5633', 'a', 'z', 'g', '3175', 's', 'l', 'l', '6811', '1821', '693', '8277', 'q', '8623', 'o']

Answer: a, c, g, l, m, n, o, p, q, s, w, z


Question: ['3637', 'g', 'w', '6005', '7643', 'd', '2307', 'n', '365', '3913', '763', 'x', '9405', '4383', 'w', '4135', '6851', 'j', 'q', '9361', 'u', 'b', '3353', 'q', '7673', 't', '9575', '9777', 't', '9247', 'q', 'm', 'v', '6875']

Answer:
b, d, g, j, m, n, q, t, u, v, w, x