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: ['n', '7337', '6887', '2203', '4663', '2837', '6451', '959', '8027', 'p', 'v', 'q', 'g', '8059', '6151', 'v', '7097', '6583', '7637', '2367', 'w', '9603', '5365', '3773', '1707', 'k', 'x', 's', 'c', 'u', '3641', '6137', '1207', 'k', '5531', '4543']

Answer: c, g, k, n, p, q, s, u, v, w, x


Question: ['8319', 'f', 'w', 'w', 'v', '6521', '4503', 'b', 's', 'b', '9651', 'k', '4635', '2195', '7537', '6839', 'i', 'd', 'b', '205', 'q', '7333', 'q', '5129', '4921', 's']

Answer: b, d, f, i, k, q, s, v, w


Question: ['f', '2627', '947', 'c', 'g', '5245', '437', '7307', '1859', 'y', 'u', 'b', '4119', '3679', 'g', 'k', '979', 'h', '5223', 'b', '5699', 'm', '539', 's', 'f', '5237', 'm', 'n', 'a', '71', 'n', '2793']

Answer:
a, b, c, f, g, h, k, m, n, s, u, y