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]: ['8235', 't', '1695', '9899', '3633', 't', '1823', 'r', 'x']
[A]: r, t, x


[Q]: ['r', 's', '3409', 'a', 'e', '6855', 'i', 'n', '8655', 's', 't', '8401', 'u', '9603', '8815', 'q', 'a', 'x', 'i', '8455', 'e', '5877', '3917', 'p']
[A]: a, e, i, n, p, q, r, s, t, u, x


[Q]: ['3229', '9859', 'd', '8617', '6035', '7531', 'r', '1219', 'x', 'n', 'u', 'c', 'p', 'l', '8881', '6141', 'g', 'c', 'i', 'o', '3053', '4409', '4699', '8157', '5407', 'n', 'f', 'm', '6309', '1353', 'u', '921']
[A]:
c, d, f, g, i, l, m, n, o, p, r, u, x