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.

['y', 'n', '6611', 'y', 'l', '4965', '8101', '8803', '7681', 'i', '4611', '1371', 'q', '741', '5929', 'b', 'b', 'b', 'u', 'g', '9639', 'a', '8741', '4889', '2707', '1983', 'o', 'l', 'c', '4587', '3893', '769', 'i', '3163', 'i', 'z', '621', 'a', '2231', 'h', '5119', 'c', '4973', '6521']
a, b, c, g, h, i, l, n, o, q, u, y, z