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.
--------
Question: ['1801', 'q', '5101', '8863', '2309', 'p', '8789', '9529', '6135', '5523', 'f', '8889', '7639', 'k', '263', '5751', '5529', 'g', '1451', '4143', 'e', '6987']

Answer: e, f, g, k, p, q


Question: ['8301', 'd', 'p', 'l', 'm', '9099', 'o', '8045', 'e', 's', 't', '8853', 'v', '6375', 'q', '2505', 's', '4219', '3587', 'g', '651', '7129']

Answer: d, e, g, l, m, o, p, q, s, t, v


Question: ['3799', '3769', '541', 'g', 'f', 'b', 'o', '6399', 'c', 'p', '7101', '6717', 'u', '4231', '6251', 't', '9035', 't', 'k', 'z', '6863', 'g', 'm', '9723', 'h', '8021', '6703', '5269', 'o', '9153', 'z', 'q', 'n', 'p', '7901', '2477', 'k']

Answer:
b, c, f, g, h, k, m, n, o, p, q, t, u, z