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: ['t', 'x', '1699', '8727']

Answer: t, x


Question: ['9113', '3625', 'u', '8189', '3649', '259', '5539', '1583', 'g', '4037', 'y', 'v', '8337', 'd', 'q', 'j', 'c', 'h', 'p', '1601', 'z', 'c', 'n', '1767', '1679', '1805', 'm', '4469', '2487', '6015', '973']

Answer: c, d, g, h, j, m, n, p, q, u, v, y, z


Question: ['5765', '6669', '2595', '4429', '2563', 'o', '9143', 'v', '7447', 'n', 'o', '827', 'n', '375', 'd', '9801', 'c', 'e', '757', 'h', '6749', '9177', '7119', 'm', 'j', '391', '1517', '2055', 'r', '731', '9621', '1421']

Answer:
c, d, e, h, j, m, n, o, r, v