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.

['o', 'c', '6469', 'x', '8815', '4441', '6193', 'u', 'm', 'a', '9879', 'p', '8335', 'c', 'z']
a, c, m, o, p, u, x, z

['7965', '6465', 'c', '7963', 'j', '6839', '9989', '1019', 'x', '1303', '2633', 'y', '6865', 'a', 'k', '635', '3719', '7229', 'k', 't', 'r', '5741', '9569', '4931', '1125', 'f', '5429', 'c', '2065', '6315', 'e', '6877', '2005', 'x', '7831', '7297', 'm', '3571', 'b', '8617', '2981', 'i', '5105', 'g', 'u']
a, b, c, e, f, g, i, j, k, m, r, t, u, x, y

['i', '7247', '8785', '1479', '5625', 'm', 'o', '261', 'e', 'k', 'u', 'z', 'c', 'i', '3061', '3337', '1307', 'e', 'p', '6455', 'g', '3283', '4655', '733', '9555', '4167', 'm', '9297', 'y', '6977', '5693', '5481', 'g', '4915']

c, e, g, i, k, m, o, p, u, y, z