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.

[EX Q]: ['t', 'r', '2959', '2517', 'a', '9959', '729', '511', 'y', 'r', '465', 'c', '687', 'm', 'b', 'm', '3449', '9713', 'g', '8275', '8823', 'a', 'z', 'w', '2185', '6283', '8457', '8137', '7163', '8329']
[EX A]: a, b, c, g, m, r, t, w, y, z

[EX Q]: ['749', 'r', 'a', 's', 't', '5905', 'm', 'd', '8437', '4583']
[EX A]: a, d, m, r, s, t

[EX Q]: ['h', 'o', '833', 'w', 'c', '6725', 'd', 'v', 'e', 't', 'x', '3193', '2235', '1731', '3349', 'i', '9123', '2643', 'k', '2605', '4997', 'b', '7923', '689', 'm', '861', 'z', 'b', 'k', 's', 'p', 'u', 'q', 'l', 'p', '8423', 'c', '4451', 'q', '6241', 'f', '9803', '5441']
[EX A]:
b, c, d, e, f, h, i, k, l, m, o, p, q, s, t, u, v, w, x, z