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]: ['1983', '1835', '6543', '6399', '4177', '9385', '7127', 'p', 'l', 'u', 'g', 't', '3423', 'g', 'b', 'l', '3133', '2429']
[EX A]: b, g, l, p, t, u

[EX Q]: ['i', '9215', 'n', 'p', '4815', '8757', 'm', '1755', 'c', 'z']
[EX A]: c, i, m, n, p, z

[EX Q]: ['2455', 'y', 'g', 'u', 'j', 'v', '3873', '5669', '4941', 'i', '2403', '4513', '5699', '6683', '6361', 'w', 'c', 'u', 'e', 'l', 's', '7179', '247', '4605', 'a', '3289', '7689', 's']
[EX A]:
a, c, e, g, i, j, l, s, u, v, w, y