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: ['s', '2507', '3091', 'g', '7643', '2573', 'w', 'r', '1977', 'q', 'c', 'j', '1335', '9671', '7317', '567', '2041', '5777', 'w', 'm']

Answer: c, g, j, m, q, r, s, w


Question: ['u', '1343', 'd', 'c', '9567', 'e', 'd', 'y', 's', '4199', '3217', '2937', '9345', 'd', 'l', '9875', '5987', 'p', '2585', '5843', '9643', '2423', 'e', 'l', 's', '3503', 'b', 'w', '9685', 'p', '6055', 'k', 'e', 'e', 't', '865', '6071', 'j', '3439', 't']

Answer: b, c, d, e, j, k, l, p, s, t, u, w, y


Question: ['5037', '5319', '91', '4019', '4351', 'h', 'y', '3931', 'b', '4005', 'z', '2825', '3003', 't', 'h', 'h', '9291', 'i', '435', '743', '7951', 'q', '3523', '1431', '8995', '4197']

Answer:
b, h, i, q, t, y, z