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: ['p', '9641', '8515', '1207', 'd', 'j', '6617', '5529', 'g', 'a', 'o', 'f', 'y', '4993', '4643', '6087', 'n', '3177', 'y', '9471', '1229', '8211', '7079']

Answer: a, d, f, g, j, n, o, p, y


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

Answer: b, l, r, v, y


Question: ['b', '8589', 'c', 'l', 'd', '611', 'q', '6219', 'w', '6577', 'r', '305', 'u', '5953', '9371', '6239', '5797', '605', '459', '5575', 'q', '297', 'p', '6187', 'r', 'x', 'l', 'f', '2047', '525', '1091', 'y', 'f', '3105', '5111', 'p', 'n', '2809', 'a', 'm', 'r', 'c', 'n']

Answer:
a, b, c, d, f, l, m, n, p, q, r, u, w, x, y