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.

Q: ['4123', '1397', '103', 'w', 't', 'j', '233', '7239', 'b', 'n', 't', '6273', 'l', '1167', '8389', '5609', '9029', '7741', 'o', 'p', '6547', '5593', 'd', '8401', 's', '4243', 's', 'u', 'm', '6659', '5691', '2105', '8897']

A: b, d, j, l, m, n, o, p, s, t, u, w
****
Q: ['1707', '381', '3957', '7853', '4987']

A: -1
****
Q: ['8377', '5803', '9983', 'd', 'm', 'b', '4339', 't']

A:
b, d, m, t
****