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: ['d', '4377', '9271', '8053', '9519']

SOLUTION: d

PROBLEM: ['d', '6003', 'k', '1987', '1877', 'a', '2615', 'n', 's', 'f', 'b', 'm', '1149', '8293', '5803', 'e', '2697', '5917', 'p', '6035', '2385', 'i', 'u', 'm', '9565', '4523', 'b', 'v', '2577', '9725', '6093', '6203', '4197', '8477', 'o', 'd', '3637', '9827', '5523', '7189', 'j', '8893', 'h', 'q']

SOLUTION: a, b, d, e, f, h, i, j, k, m, n, o, p, q, s, u, v

PROBLEM: ['k', 's', '7189', '2053', 'l', '301', '9227', 'd', 'k', '5467', '573', 'b', 'b']

SOLUTION:
b, d, k, l, s