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: ['8235', 't', '1695', '9899', '3633', 't', '1823', 'r', 'x']

Answer: r, t, x


Question: ['o', 'd', '6495', '5211', '341', 'v', '385', 'v', 'g', 'v', 'l', '7631', '2675', 't']

Answer: d, g, l, o, t, v


Question: ['k', '6459', '5039', 'k', '8071', '9821', 'f', '5247', 'v', '7187', 'p']

Answer:
f, k, p, v