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: ['c', '4881', '6893', '3729', 'j', '2385', 'q', 'v']

SOLUTION: c, j, q, v

PROBLEM: ['7073', 'd', 'e']

SOLUTION: d, e

PROBLEM: ['u', 'n', '8971', '55', 'm', 'e', 'm', 'b', '2587', '5617', '1967', 'f', '8221', 'h', '1317', '2385', 'd', '2245', '1763', '8445', 'y', 'p', '387', '5687', 'f', '6991', 'e', '1669', 'o', '207', '1039']

SOLUTION:
b, d, e, f, h, m, n, o, p, u, y