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]: ['8051', 'h', 'g', 's', 't', 'p', 'w', 'x', 's', '8521', 'm', '9719', 'j', 'n', 'i']
[A]: g, h, i, j, m, n, p, s, t, w, x


[Q]: ['4927', 'h', 'x', '4719', 'j', 'f', '7797', 'l', 'i', 'q', 'x', 'i', 'k', '3215', 'k', '1625', 'g', 't', 'i', 'w', 'n', '6659', '8355', '831', 'h', '9723']
[A]: f, g, h, i, j, k, l, n, q, t, w, x


[Q]: ['f', '2401', '4777']
[A]:
f