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: ['6643', '6757', 'h', '1033', 's', 'c', '2003', 'p', '5483', 'f']

SOLUTION: c, f, h, p, s

PROBLEM: ['z', '3219', '6399', '2357', '7597', '357', 'k', 'k', 'u', 'd', '6115', 'w', '2921', '8809']

SOLUTION: d, k, u, w, z

PROBLEM: ['755', 's', 'a', '4883', 'a', 's', '2659', 'j', '2593', '9863', 'q', '6227', 'o', '7745']

SOLUTION:
a, j, o, q, s