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: ['l', 'u', '3901', '341', '5801']

Answer: l, u


Question: ['8301', 'd', 'p', 'l', 'm', '9099', 'o', '8045', 'e', 's', 't', '8853', 'v', '6375', 'q', '2505', 's', '4219', '3587', 'g', '651', '7129']

Answer: d, e, g, l, m, o, p, q, s, t, v


Question: ['1483', '7841', '6587', '5323', '7985', '8851', '7005', '1617', 'v', 'i', '4631', '1913', 'p', 'x', 'q', '6031', 's', 'i', 't', '5637', 'd', 'p', '5793', 'd', 'u', '3821', '9897', '5669', 'q', 'b', 't', 'q', 'm']

Answer:
b, d, i, m, p, q, s, t, u, v, x