Given the task definition and input, reply with output. 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.

['9285', '3357', '1589', '7545', '503', '4011', 'n', '4183', '7799', 'z', '5065', '945', 'j', 'n', 'm', '4719', '9267', 'z', 'u', '1161', '9727', 'o', 'm', '8035', 'g', 'i', '7039', '1067', 'a', '4753', '1203', 'q', 'r', 'g', '731', '5269']
a, g, i, j, m, n, o, q, r, u, z