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.

['477', '3931', 'g', '5967', 'm', '9845', '1607', 'a', '1749', 'k', 'j', '7945', '9125', 'v', 'n', 's', '5185', '1117', '17', 'x', '4149']
a, g, j, k, m, n, s, v, x

['7591', '1403']
-1

['2627', 'u', 'm', 'c', 'q', 'b', '2235', '5927', '8697', '323', '8917', '2737', '5699', 'b', '9993', 'o']

b, c, m, o, q, u