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: ['u', 'd', '4193', '5687', 'p', 'r', '7787', 't']

Answer: d, p, r, t, u


Question: ['1447', 'q', '9529', '2971', 's', '7351', '6753', '3493', 'v', 'c', 'x', '3097', '9145', 'b', 'e', 'b', '2967', '6933', 'e', 's', 'v', 'f', 'z', 'r']

Answer: b, c, e, f, q, r, s, v, x, z


Question: ['k', '7557', '3069', '5341', '4281', '3427', '7461', 'r', '4683', '8883', '9419', 'h', 'n', '1567', 'p', 'f', 'f', 's', 'c', '8285', '4371', 'h', 's', 'd', '8579', 'q', '321', '5325', '8229', 'f', 'f', 'h', '7741', '2381', 'm', '6505']

Answer:
c, d, f, h, k, m, n, p, q, r, s