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', '8389', 'j', '6113', '5843', 'f']

SOLUTION: c, f, j

PROBLEM: ['d', '771', '4193', 'e', '1537', 'a', 'q']

SOLUTION: a, d, e, q

PROBLEM: ['4473', 'w', '5775', '6839', '5639', '8799', 'v', '1369', 'e', 'p', '3443', '7111', '4059', 'q', 'g', '117', '925', '4013', 't']

SOLUTION:
e, g, p, q, t, v, w