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: ['u', 'd', '4193', '5687', 'p', 'r', '7787', 't']

Answer: d, p, r, t, u


Question: ['2995', '8179', '8131', '5655', 'j', 'q', 'l', '3193', '1823', 'y', 'n', '7645', 's', '5665', 'r']

Answer: j, l, n, q, r, s, y


Question: ['6031', 'x', '6699', '451', '4537', '6013', '8551', 'k', 's', '7771', 't', 'e', 'o', 'q', '8433', 'h', 'c', 'e', '8045', '4675', '1791', 'p', '9', 'j', '4285', '277', 'd', 'y', 'i', '4671', '3933', '9221', '4435', 'l', 'x', 'e', '7189', '4857', '8767', '6983', 'a', '5351']

Answer:
a, c, d, e, h, i, j, k, l, o, p, q, s, t, x, y