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: ['w', '8777', 'y', 'e', '8015', 't', 'w', '53', '9149', 'e', 'k', '1837', 'b', 's', '4007', '4905']

Answer: b, e, k, s, t, w, y


Question: ['3127', '9253', '5667', '9453']

Answer: -1


Question: ['7007', 'u', 'j', '2139', '9595', '7037', 'x', 'l', 'f', '5009', '2815', 'r', '3445', '2863', '6803', 'd']

Answer:
d, f, j, l, r, u, x