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: ['i', 's', 'f', 'i', '2293', '245', '4983', 'h', 'h', '6203', '8703', '1613', 'h', 'o', '3635', '8069', '2829', '1939', 'u', 'm', '5305', 'n', 'k', '9367', 'u']

Answer: f, h, i, k, m, n, o, s, u


Question: ['o', 'v', 'w', '7939', '571', '395', '3707', 'm', 'd', 'u', 'o', 'r', '4211', '9645', '8731', '2441', 'y', '8147', '8809', 'e', 'b', '6835', 'i', '2083', 't', '3481', 'f', 'f', '5559', '3601', 'e', '5637', '5185', 't', '6777', '3419', '8637', 'p', 's', 'o', 'x']

Answer: b, d, e, f, i, m, o, p, r, s, t, u, v, w, x, y


Question: ['6975', '6051', 'r', '4413', 'j', '5315', '9291', '4479', 'i', '4597', 'u', '2649', '2503', 'n', 'p', '4233', '1611', '1867', 'l', '1645']

Answer:
i, j, l, n, p, r, u