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]: ['1979', 'b', 't', '1101', '7953', '2451', '7539', '6833', 'u', '49']
[A]: b, t, u


[Q]: ['j', 'y', '9907', 'a', '5715', 'l', '9817', '1949', '2697', '2255', '9571', '8957', '9329', '6055', 'z', 'q', '1185', '4593']
[A]: a, j, l, q, y, z


[Q]: ['f', 'n', '1201', 'w', '5271', '5821', '6297', '8133', '279', 'k', '6969', 's', 'u', '7187', 'g', 'r', 'f', 't', '5103', 'v', 'e', 'd', '7845', 'v', 'i', 'w', 'e', '8257', 'd', 'z', 'u', '7923', 'x', '761', 'k', '2607', 'x']
[A]:
d, e, f, g, i, k, n, r, s, t, u, v, w, x, z