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: ['6027', 'v', 'b', 'l', '7853', 'r', 'y', '2919', '3831']

Answer: b, l, r, v, y


Question: ['b', 'd', '8153', 'u', '3695', '5317']

Answer: b, d, u


Question: ['t', '4379', '4591', 'm', 's', '3761', '5497', '327', '2835', 'm', '2491', '3049', '8483', '1739', '5301', 'h', '3761', 'f', 'k', '6171', 'm', '9393', '799', 'p', 'o', '9637', '5289', 't', 'v', 'm', '8537', 'c', '6233', '4545', 'l', '3845', 'x', 'f', '7671', 'n', '4343', 'b', 'k', 'n', '245']

Answer:
b, c, f, h, k, l, m, n, o, p, s, t, v, x