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]: ['5011', 'l', '925', 'e', 'b', '3077', 'm', '4541', '781']
[EX A]: b, e, l, m

[EX Q]: ['k', 'v', 'e', '6377', 'y', '3585', '4535', 'f', 'g', 'm', 'f', '8369', 'v', '7445', '4527', '9383', 'n']
[EX A]: e, f, g, k, m, n, v, y

[EX Q]: ['2873', 'e', 'o', 'g', '9201', '2151', 'a', '3167', '9673', 'x', 'g', '3313', 'p', 'i', '5279', '6527', '669', '4891', 'a', '9207', '7851', '5589', '5119', '6707', 'v', 's', '3941', '2811', '4159', 'n', 'i', '3927', '3417', 'f', 'g', 'e', '3063', '6477', 't', '8909', 'w', 'u', '445', 'f', '5901']
[EX A]:
a, e, f, g, i, n, o, p, s, t, u, v, w, x