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.

['l', 'u', '3901', '341', '5801']
l, u

['f', '9027', 'z', '9601', 'w', '7747', '1135', 'j', '1871', 'd', 'u', 'f', 'd', 'x', 'k', '2009', 't', '4625', 'm', '1619', 'm', 'm', '3107', 'x', '3957', '2495', 'j', '201', 'a', '4635', 'r', '7407', 'b', 'r', 'z']
a, b, d, f, j, k, m, r, t, u, w, x, z

['f', '6275', 'p', '7921', '2071', 'g', 'f', 'z', 'u', 's', '1853', 'f', 'x', '9965', 'f', 't', 'j', 'i', '113', '1421', 'c', '2169', 'o', '4231', '313', 'k']

c, f, g, i, j, k, o, p, s, t, u, x, z