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', '8637', '7415', '227', 'c', '4501', '9367', 'i', '4973', '4767', 'q', 'a', 'h', 'c', '8139', 'j', '1423', 'g', '8387', 'y', 'x', '5093', '2213', 'j', 'm', 'l', 'p', '8479', '5217', '3255', 'y', '9055', 'c', '7543', '7641', 'v', 't', 'w', '2549']
a, c, g, h, i, j, l, m, p, q, t, v, w, x, y