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.

['4299', 'b', '4171', '7639', '6609', '927', '5249', 'o', 'p', '9851', 'e', '1311', '3777', '7799', '7687', '8809', 'c', 'r', '47', '1925', '1847', 'r', 'd', 'r', '1871', '5935', 'r', '2283', 'p', 'p', '2727', 'c', 'i', '7357', 'y', '5103', '6115', 'q', 'w', 'u', '9201', '4221', '7717', 'o']
b, c, d, e, i, o, p, q, r, u, w, y

['2819', 'k', 'u', 'a', '4575', 'a', 't', 'a', 'f', '1507', '415', 'w', 'o', 'o']
a, f, k, o, t, u, w

['j', 'u', '9009', '3489', 'j', 'v', 'r', 'q', '1197', 'b', 'e', 'p', 'p', 'e', '887', '4535', 'j', '7475', '4355', 'n', 'y', 'a', 'e', '5851', 'b', '4283', '423', 'g', 'i', 'e', '3463', '9725', '859', 'e', 'f', 'd', '875', 'd', 'o', 'c', 'd', '4091', 'x', '3857']

a, b, c, d, e, f, g, i, j, n, o, p, q, r, u, v, x, y