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]: ['u', 'o', 'b', 'b', '5873', 'w', 'v', '4171', '7957', '3501', '2563', 'l', 'q']
[EX A]: b, l, o, q, u, v, w

[EX Q]: ['3947', '4809', 'b', 'a', '4769', '4179', '535', '5965', 'f', 'j', '2265', 'w', '3103', 'u']
[EX A]: a, b, f, j, u, w

[EX Q]: ['8239', '9033', '9959', '6235', 's', 'f', 'b', '5619', '871', 'y', '2339', '203', 'x', '793', 'k', '8345', 'y', '4765']
[EX A]:
b, f, k, s, x, y