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: ['f', '217', '449', 't', 'j', '4097', '5561', '8317', '647', 'u', 'b', '7833', 'r', '9011', 'z', '2753', '2183', 'z', 'o', 'g', '7541', 'b', '8795', '327', 'v', 'e', 't', 'l', '4909', 'k', '7681', 'r']

Answer: b, e, f, g, j, k, l, o, r, t, u, v, z


Question: ['3995', 'n', 'z', '8389', '7857', '3005', 'i', 'e', '1117', 'z', '8251', 'r', 't']

Answer: e, i, n, r, t, z


Question: ['b', 't', '7369', 'd', 't', 'z', '6359', '9799', '1381', 'x', 'l', 'r', 't', 't', 'x', '4767', 'w', 'c', '8233', '6843', '5021', 'd', '8855', 'd', '3953', 'v', '4235', 'n', '2105']

Answer:
b, c, d, l, n, r, t, v, w, x, z