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]: ['m', '3809', 'l', 'k', '1929', '7963', 'n', 'u', '2125', 'g', 'o', '8325', 'o', 'h', 'y', '3025', 'e', 'e', 'c', 'x', '8445', '4979', 'z', 'f', '4201', '4765', 'g']
[EX A]: c, e, f, g, h, k, l, m, n, o, u, x, y, z

[EX Q]: ['7989', '6897', 'o', 'v', '5687', '2933', 'w', '8207', 'y', 's', 'w', '3013', 'h']
[EX A]: h, o, s, v, w, y

[EX Q]: ['g', 'r', '2917', '813', 'r', 'r', '6763', 'h', '7151', 'f', 'x', 'd', 'y', 'u', 'd', 's', 'm', 'p', '4881', '8807', 'y', '5129', '4867', '8949', 'd', '5037', '7311', '4149', '847', '9651', '1851', 'k', 'm', '1787', 'z', '3025', '4619']
[EX A]:
d, f, g, h, k, m, p, r, s, u, x, y, z