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', 'i', '1185', '3795', '5417', 'k', 'b', '2629', '2635', 'z']

Answer: b, i, k, u, z


Question: ['g', 'p', '2925', 'n', 'o', 'y', '6381', 'l', '4963', 'g', 'm', 'u', 't', '9389', '3787', '7713', '1251', '779', 'i', 'w', '9869', 'y', 'y', '3881', 'k', 't']

Answer: g, i, k, l, m, n, o, p, t, u, w, y


Question: ['221', 'p', 'w', '5857', 'f', 'c', '1949', '1863', 'n', '2545', 'p', 'c', '441', 'b', 'x', 't', 'f', 'r', 'x', 'g', '5119', 'e', 'j', '3901', '5565', 'f', 'w', '4307', 'j', '3055', 'c', 'f', 't', '8159']

Answer:
b, c, e, f, g, j, n, p, r, t, w, x