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.

['4925', 'i', 'q', 'k', '7615', 'r', '7217', 'o', '8097', '9151']
i, k, o, q, r

['c', '7039', 'g', '1899', 'r', '507', 'c', '2587', '3865', '1729', '3927', 'r', '3535', '2791', 'm', 'l', 'r']
c, g, l, m, r

['2471', '4527', 'h', 't', 'n', '3571', '8349', '9449', 'f', 'b', 'p', '9101', '4939', 'd', '4537', '4299', '9541', 'q', 'c', '8765', 'b', 'k', '3789', '4821', '9169', 'b', 'r', 'b', 'o', 'a', 'o', 'i', 'l', 'f', 'j', '8943', '9509', 'q', '4743', '8047', 'c', 'i', 't']

a, b, c, d, f, h, i, j, k, l, n, o, p, q, r, t