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]: ['6697', 'j', '1571', '4989', 'o', '1143', 'i', '2969', '2541', '4899', 'i', '4751', 'n', 'b', '801', '4357', '3855', '49', 'm', '211', '7281', '121', '5231', '8313', '8967', '8043', '7699', 'r', '4315', '8637', '3339', '4437']
[EX A]: b, i, j, m, n, o, r

[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]: ['5395', '2443', 'n', '2037', 'p', '5395', 't', '4075', 'k', 'l', 'k', 'j', 'm', '9317', 'r', 'z', '1427', 'a', 'g', 'p', 'c', 'v', 'p', 'v', 'z', 'x', '1171', '317', '9289', '5619', '3743']
[EX A]:
a, c, g, j, k, l, m, n, p, r, t, v, x, z