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.

[Q]: ['i', '4447', 'g', 'o', 'j', 'p', 'l', 'q', 'o', '8777', 'r', 'v', '961', '6083']
[A]: g, i, j, l, o, p, q, r, v


[Q]: ['g', 'u', 'q', '1375', '9491', 't', 'w', 'c', 'v', 'y', '3169', '1607']
[A]: c, g, q, t, u, v, w, y


[Q]: ['w', 'w', '7867', '7697', 't', '521', 'n', 'z', 'i', '8589', '2239', '4609', 'u', '4225', 'l', 'y', 'd', 'r', '4305', '605', '5383', 'a', 'z', 'h']
[A]:
a, d, h, i, l, n, r, t, u, w, y, z