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: ['7417', '2597', '2633', '7721', 'v', 'l', 'p', '4389', 'l', '3965', '6279', 'm', 'v', 'o', 'd', 'o', 'h', 'd', 'r', 'e', '8993', '2711', 'o', 'q', '1399', 'i']

SOLUTION: d, e, h, i, l, m, o, p, q, r, v

PROBLEM: ['1429', '7273']

SOLUTION: -1

PROBLEM: ['e', 'g', '2945', 'f', '4691', '2467', '375', '2925', 'z', '7787', 'm', 'j', 'e', '9867', '2429', '7579', '9283']

SOLUTION:
e, f, g, j, m, z