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.

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

['q', 'g', 's', 'g', 'z', '987', '777']
g, q, s, z

['6767', '5797', 'r', '9923', '4377', 'i', 'x', '5805', '4011', '5701', 'q', 'c']

c, i, q, r, x