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', '4731', 'l', 'p', '1997', '601', 'n', 'l', 'p', '211', '7355', '6537', 'w', 'x', '1741', '8145', '3689', 'm', 'y', '6945']

Answer: l, m, n, p, u, w, x, y


Question: ['h', 'b', '9601', 'h', 'h', 'h', '8099', '8265', 'i', 'd', '8791', 'p', '8059', '4309', '501', '2581', '9837', '157', '4785', '5925', 'q', '8491', '4779', 'r', 'l', 'k', '3679', 'v', 'g', 'g', '9731', '1909', '9783', 'f', '4293', '5009', 'o', '3057', '3157', 'c', '5587', 'b', 'f', 'd', 'k']

Answer: b, c, d, f, g, h, i, k, l, o, p, q, r, v


Question: ['i', '1277', '1191', 'j', '1821', '933', 'q', '7485', '1919', 'g', '4985', 'i', '9919', 'q', '2601', 'q', '29', 'i', '5561', 'v', 'z', '2855', '6109', '7751', 't', '5763', 'q', 'm', 'd', '5871', 'a', 'q', '1241', '3823', '6417', '1877', 'z', '5789', '3673', 'z', 't', 'd']

Answer:
a, d, g, i, j, m, q, t, v, z