Q: 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.
['1991', 'b', '8165', 'f', 'k', 'g', '985', '5271', '1845', '261', 'r', 'g', 'p', '5417', '697', 'a', 'l', '3839', '1665', 'q', '7207', 'r', '3285', '129', '2213', 'f', 'f', 'u', 'c', 'm', 'v', '4603', 'n', 'n', '3525']
A:
a, b, c, f, g, k, l, m, n, p, q, r, u, v