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.

['z', '2519', '4799', '4715', '7165', 'r', 'r', 'l', 'n', '6925', '8935', '9795', '5489', 'v', 'u', '6527', '2241', 'u', 'c', 'w', '9755', 'w', '9823', 'g']
c, g, l, n, r, u, v, w, z

['k', '8917', '3773', '6723', 'r', 'z', '3265', 'o', 'f', 'q', '9343', 'f', '1925', 'u', 'b', 'o', '5275', 'b', 'n', 'd', 'j', '4825']
b, d, f, j, k, n, o, q, r, u, z

['8129', '691', '3027', 'f', 'l', '6299', 'd', '5007', '8783', 'b', '6949', 'a', '299', '6055', 'k', '1583', 'm', '5929', 'i', '3159', 't', '5415', 'l', 'y', '1361', '1471', '6765', '4335', 'w', '787', '6125', '2979', '9207', '1221', '6585', 'i', '4063', '7767', '8209', 'j', '3189', 'x', '5081', '4861', '3635']

a, b, d, f, i, j, k, l, m, t, w, x, y