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: ['e', '1251', 'y', '6689', '6389', 'h', 't', '503', '5093', 'e', '923', '7051', 'm', 'u', '4501', '3289', '6887', '8341', 'o', '3671', 'n', 'w', '7749', 's', 'j', 'o', '8429', 'q', 'v', 'p', 'd', 'g', 'i', 'f']

Answer: d, e, f, g, h, i, j, m, n, o, p, q, s, t, u, v, w, y


Question: ['l', 'g', 'd', 'p', '8163', '6643', 'o', 'p', 'm']

Answer: d, g, l, m, o, p


Question: ['7867', '5961', 't', '5589', 'a', 'v', 'm', 'm', '2593', '7087', 'w', '1571', 'm', 's', '57', 'w']

Answer:
a, m, s, t, v, w