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: ['2165', 'f', '5081', 's']

SOLUTION: f, s

PROBLEM: ['4371', '9499', 'e', 'w', '9969', '8367', '2897', '1745', 'i', '7049', '9773', 'h', '9649', 'u', '4673', '8513', '8547', 'z', '1995', '7739', '2215', '171', 'c', '7527', '2479', 't', '5223', 'p', '2313', '3243', '2281', 'r', 'c']

SOLUTION: c, e, h, i, p, r, t, u, w, z

PROBLEM: ['u', '8193', 'a', 'u', '1599', '8903', '9223', 'f', '4493', 'p', 'x', 'c', 'x', '9317', 'i', '6341', '5185', '2003', '8109', 'q', '2459', '8449', '2437', '4451', 'k', 'h', '3933']

SOLUTION:
a, c, f, h, i, k, p, q, u, x