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: ['t', 'u', 'y', 'y', 'b', 'x', 'q', '3713', '2679']

Answer: b, q, t, u, x, y


Question: ['3611', '6825', 'j', 'e', 'r', 'a', '8889', 'y', 'x', 'k', '2651', '4545', '2289', 'r', 'q', '3163', 'a', 'i', 'j', 't', 'b', '2673', '4307', 'q', '5839', 'w', 'g', '6221', 'g', 'h', 'h', '5815', 'n', '3551', '7709', 'z', '2281', '7987', 'w', 'a', '2319', '3337', '3409']

Answer: a, b, e, g, h, i, j, k, n, q, r, t, w, x, y, z


Question: ['w', '7573', 'c', 'a', 'o', '8261', 't', 'm', 'f', '7577', '531', 'l', '8539', '9745', '8921', '7257', '8939']

Answer:
a, c, f, l, m, o, t, w