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.

['315', '9975', '3013', 's', '6131', 'e', 'e', 'u', 'a', '1729', 'g', 't', 'y', 'f', '7523', 'e', 'g', '489', 'm', 'p', 'f', 'e', '2077', 'e', 'g', 'c', 'l', '6389', 'k', 'b']
a, b, c, e, f, g, k, l, m, p, s, t, u, y

['7441', '7967', '2011', '1383', 'i', '3623', 'b', 'y', 'e', '1593', 'r', 'a', 'd', 'b', '6159', '3931', '989', '435', 'o', 'y', 'j', 'w', '7669', 'y', '5781', 'u', '531', '7467', '3971', '8139', 'w', 'a', '5113', '9461', '8377', '7431', '6975', '6055', '7307', 'v']
a, b, d, e, i, j, o, r, u, v, w, y

['3175', 'g', 'r', 'l', 'g', '629', 'w', '8489', '7031', 'q', '3925', '9739', 'l', 'p', '4051', 'c', 'g', '7623', 'v', 'f', 'w', 'v', 'y', '7045', 't', '9385', 'r', '683', 'b', 'y', 'h', 'y', '1003', 't', '1957', 'e', '255', 'l', '1855', '8665', 'w', '3713', '2317']

b, c, e, f, g, h, l, p, q, r, t, v, w, y

