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: ['d', 'o', '7643', '9065']

Answer: d, o


Question: ['j', 'y', '9907', 'a', '5715', 'l', '9817', '1949', '2697', '2255', '9571', '8957', '9329', '6055', 'z', 'q', '1185', '4593']

Answer: a, j, l, q, y, z


Question: ['7635', '9281', '5901', 'p', '8791', 's', 'r', 'h', '3579']

Answer:
h, p, r, s