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: ['5553', 'f', '3881', '8867', 's', 'd', 'a', '375', '7889', '3949', '2905', 'w', 'q', 'q', 'd', '4203', 'i', '2601', 'y', 'p', 'k']

Answer: a, d, f, i, k, p, q, s, w, y


Question: ['887', 'p', '3819', '2727', '1407', 'b', 'n', '737', 'd', 'w', 'q', '6877']

Answer: b, d, n, p, q, w


Question: ['f', '2857', 'i', '699', 'd', 'q', '1979', '8209', 'x', 'g', '1927', '1491', 'm', '4169', '3217', '639', 'u', 'm']

Answer:
d, f, g, i, m, q, u, x