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.

['5971', 'x', 'c']
c, x

['h', '1797', '8211', 'n', 'r', '7707', '2063', '4655', 'x', '5521', '8327', 'g', '7659', 'i', 'x', 'w', '9465', '4625', 'q', '5377', 'r', '225', 'r', 'i', 'e', '4163', 'g', 'g', '3537', 's']
e, g, h, i, n, q, r, s, w, x

['y', 'u', 'c', '5909', 'x', '9865', 'e', 'h', '5125', '4719', 'w', '8855', 'i', 'd']

c, d, e, h, i, u, w, x, y