TASK DEFINITION: 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.
PROBLEM: ['9833', '3383', 'h', '3545', '2899', 'y', 'p', 'q', '1901', '3317', '5641', 'v', 'c', 'u', '5521', 'e', '7997', '2439', '5573', '4119', 'k', '8291', '1009', '8253', '405', '233', 'p']

SOLUTION: c, e, h, k, p, q, u, v, y

PROBLEM: ['a', 'a', 'b']

SOLUTION: a, b

PROBLEM: ['287', 'h', '4419', 'o', 'h', '2177', '91', 'j', 's', 'u', '1837', '2127', 'e', 'v', 'i', '5169']

SOLUTION:
e, h, i, j, o, s, u, v