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: ['o', 'c', '6469', 'x', '8815', '4441', '6193', 'u', 'm', 'a', '9879', 'p', '8335', 'c', 'z']

A: a, c, m, o, p, u, x, z
****
Q: ['u', 'o', 'b', 'b', '5873', 'w', 'v', '4171', '7957', '3501', '2563', 'l', 'q']

A: b, l, o, q, u, v, w
****
Q: ['5999', 'e', 'v', '3685', 'l', '6779', '9007', 'f', 'h', '3197', 'k', 'p', '9911', '1657', 'c', 'v', '1293', '6101', 't', 'b', '9871', '3679', '9571', '2895', 'm', 'r', 'a', '3403', '3689', 'g', 't', '2187', '8507']

A:
a, b, c, e, f, g, h, k, l, m, p, r, t, v
****