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.

['7187', '7081', 'j', 'i', '3725', '6333', 'h', 'f', '6639', 'r', 'n', '3559', '2785']
f, h, i, j, n, r

['8319', 'f', 'w', 'w', 'v', '6521', '4503', 'b', 's', 'b', '9651', 'k', '4635', '2195', '7537', '6839', 'i', 'd', 'b', '205', 'q', '7333', 'q', '5129', '4921', 's']
b, d, f, i, k, q, s, v, w

['7143', '3007', 'n', '3705', '7343', '2593', '501', 'w', 'c', 'h', '4195', '101', '5447', 'q', 'd', '8155', 'd']

c, d, h, n, q, w