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: ['1983', '1835', '6543', '6399', '4177', '9385', '7127', 'p', 'l', 'u', 'g', 't', '3423', 'g', 'b', 'l', '3133', '2429']

Answer: b, g, l, p, t, u


Question: ['9223', 'w', '8631', '4453', '9975', 'y', '9747', 'g', '7077', '2593', '6015', 'n', '7345', 'i', '7807', '299', 'q', '3629', '2545', 'k', 'm', 'q', '5155', '5633', 'x', 'q', 'i', '27', 'f', '7919', 'p', '4835']

Answer: f, g, i, k, m, n, p, q, w, x, y


Question: ['c', '8715', '2071', 's', 'g', '6313', '1833', 'i', '4081', '1749', '2477', 'b', '1181', '4711', '1779', 'r', '9771', '3703', 'i', '8837', '4813', '3483', '8543', 'o', 'k', 'm', '573', 'b', 'e', '391', 'j', '821', 'z', 'd', 'o', '2423', 'w', 'u', 'k']

Answer:
b, c, d, e, g, i, j, k, m, o, r, s, u, w, z