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.

['7965', '6465', 'c', '7963', 'j', '6839', '9989', '1019', 'x', '1303', '2633', 'y', '6865', 'a', 'k', '635', '3719', '7229', 'k', 't', 'r', '5741', '9569', '4931', '1125', 'f', '5429', 'c', '2065', '6315', 'e', '6877', '2005', 'x', '7831', '7297', 'm', '3571', 'b', '8617', '2981', 'i', '5105', 'g', 'u']
a, b, c, e, f, g, i, j, k, m, r, t, u, x, y

['r', 'n', '7583', '8697', '7927', 'l', '5003', '1363', 'p', 'e', 'q', '6227', '6915', '8619', '9011', 'n', '3063', '3799']
e, l, n, p, q, r

['7727', '347', 'i', 'u', 'b', '7025', '5889', 'm', 'o', 'w', 'c', 'y', 'm', '9187', 'o', 'e', 'p', 'g', 'a', 'c']

a, b, c, e, g, i, m, o, p, u, w, y