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.

[EX Q]: ['w', 'g', '1649', 'a', '2115', '6763', 'r', 't', 'l', 's', 'y', '5659', 'a', 'b']
[EX A]: a, b, g, l, r, s, t, w, y

[EX Q]: ['5973', 'h', '4081', 'i', '8059', 'w', 'j', '6175', 'w', '8685', '5811', 'k', 'n', '5577', '9817', 'v', '8617', 'u', 'y', '3921', 'b', '1027', '5405', 'a', '3501', '6659', 's', 'e', '157']
[EX A]: a, b, e, h, i, j, k, n, s, u, v, w, y

[EX Q]: ['7029', 'y', 'v', 'b', 'l', 'w', 's', 'q', '2079', 'v', '7767', 'k', 'z', '6949', '5217', 'h', 'b', 'g', 'u', '8901', '4185', 'i', 'l', 'r', '5479']
[EX A]:
b, g, h, i, k, l, q, r, s, u, v, w, y, z